From 90f91153173992335661c2a347f1558a301e5185 Mon Sep 17 00:00:00 2001
From: "Ben \"root\" Anderson" <roothorick@gmail.com>
Date: Sat, 26 Oct 2013 18:03:46 -0500
Subject: [PATCH] OpenGL detection overhaul. 1) Fix some bad quoting 2) More
 consistent formatting 3) Add GLU detection 4) Rewrite GLEW detection from
 scratch and move it to opengl.m4 where it belongs.

---
 autoconf/m4/opengl.m4 | 34 +++++++++++++++++++++++++++++-----
 configure.ac          | 17 -----------------
 2 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/autoconf/m4/opengl.m4 b/autoconf/m4/opengl.m4
index 9337b977cb..7ab304f914 100644
--- a/autoconf/m4/opengl.m4
+++ b/autoconf/m4/opengl.m4
@@ -8,14 +8,38 @@ AC_DEFUN([SM_OPENGL],
 	
 	GL_LIBS=""
 	
-	AX_CHECK_LIB_USING_HEADER(GL, 'glBegin(GL_POINTS)', GL/gl.h, [GL_LIBS="-lGL"])
+	AX_CHECK_LIB_USING_HEADER(GL, glBegin(GL_POINTS), GL/gl.h, [GL_LIBS="-lGL"])
 	
 	if test "$GL_LIBS" = ""; then
-	AX_CHECK_LIB_USING_HEADER(opengl32, 'glBegin(GL_POINTS)', GL/gl.h, [GL_LIBS="-lopengl32"])
-	fi
-	if test "$GL_LIBS" = ""; then
-			AC_MSG_ERROR("No usable OpenGL library found.")
+		AX_CHECK_LIB_USING_HEADER(opengl32, glBegin(GL_POINTS), GL/gl.h, [GL_LIBS="-lopengl32"])
 	fi
 	
+	if test "$GL_LIBS" = ""; then
+		AC_MSG_ERROR("No usable OpenGL library found.")
+	fi
+	
+	AX_CHECK_LIB_USING_HEADER(GLU, gluGetString(GLU_VERSION), GL/glu.h, [GLU_LIBS="-lGLU"])
+	
+	if test "$GLU_LIBS" = ""; then
+		AX_CHECK_LIB_USING_HEADER(glu32, gluGetString(GLU_VERSION), GL/glu.h, [GLU_LIBS="-lglu32"])
+	fi
+	
+	if test "$GLU_LIBS" = ""; then
+		AC_MSG_ERROR("No usable GLU library found.")
+	fi
+	
+	AX_CHECK_LIB_USING_HEADER(GLEW, glewInit(), GL/glew.h, [GLEW_LIBS="$LIBS -lGLEW"])
+
+	if test "$GLEW_LIBS" = ""; then
+		AX_CHECK_LIB_USING_HEADER(glew32, glewInit(), GL/glew.h, [GLEW_LIBS="$LIBS -lglew32"])
+	fi
+	
+	if test "$GLEW_LIBS" = ""; then
+		AC_MSG_ERROR("No usable version of GLEW found.")
+	fi
+
+	AC_CHECK_DECL(GLEW_VERSION_2_1, , AC_MSG_ERROR("GLEW 1.3.5 or newer is required."), [#include <GL/glew.h>])
+	
+	GL_LIBS="$GL_LIBS $GLU_LIBS $GLEW_LIBS"
 	AC_SUBST(GL_LIBS)
 ])
\ No newline at end of file
diff --git a/configure.ac b/configure.ac
index ff542c4093..67c8343f8d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -348,23 +348,6 @@ AC_CHECK_DECL(strtof, , AC_DEFINE([NEED_STRTOF],1,[Need strtof]), [#include <std
 
 AC_CHECK_DECLS([SIGPWR, SIGUSR1],,,[#include <signal.h>])
 
-have_glew="no"
-AX_CHECK_LIB_USING_HEADER(GLEW, 'glewInit()', GL/glew.h,
-	have_glew="yes"
-	LIBS="$LIBS -lGLEW", 
-	,
-	[$LIBS])
-	
-test $have_glew = "no" && { AX_CHECK_LIB_USING_HEADER(glew32, 'glewInit()', GL/glew.h,
-	have_glew="yes"
-	LIBS="$LIBS -lglew32",
-	,
-	[$LIBS]) }
-
-test $have_glew = "no" && AC_MSG_ERROR("Could not find GLEW.")
-
-AC_CHECK_DECL(GLEW_VERSION_2_1, , AC_MSG_ERROR("GLEW 1.3.5 or newer is required."), [#include <GL/glew.h>])
-
 AC_ARG_ENABLE(tests, AS_HELP_STRING([--enable-tests],[Build test programs]), enable_tests=$enableval, enable_tests=no)
 AM_CONDITIONAL(BUILD_TESTS, test "$enable_tests" = "yes" )