Update zlib from version 1.2.5 to 1.2.11

extern/zlib/INDEX

@@ -7,6 +7,9 @@ Makefile.in     template for Unix Makefile
 README          guess what
 configure       configure script for Unix
 make_vms.com    makefile for VMS
+test/example.c  zlib usages examples for build testing
+test/minigzip.c minimal gzip-like functionality for build testing
+test/infcover.c inf*.c code coverage for build coverage testing
 treebuild.xml   XML description of source file dependencies
 zconf.h.cmakein zconf.h template for cmake
 zconf.h.in      zconf.h template for configure
@@ -14,9 +17,11 @@ zlib.3          Man page for zlib
 zlib.3.pdf      Man page in PDF format
 zlib.map        Linux symbol information
 zlib.pc.in      Template for pkg-config descriptor
+zlib.pc.cmakein zlib.pc template for cmake
 zlib2ansi       perl script to convert source files for C++ compilation
 
 amiga/          makefiles for Amiga SAS C
+as400/          makefiles for AS/400
 doc/            documentation for formats and algorithms
 msdos/          makefiles for MSDOS
 nintendods/     makefile for Nintendo DS
@@ -56,10 +61,8 @@ uncompr.c
 zutil.c
 zutil.h
 
-                source files for sample programs:
-example.c
-minigzip.c
-See examples/README.examples for more
+                source files for sample programs
+See examples/README.examples
 
-                unsupported contribution by third parties
+                unsupported contributions by third parties
 See contrib/README.contrib