--- ./source/Irrlicht/libpng/pngpriv.h.orig	2016-12-17 13:35:22.000000000 -0800
+++ ./source/Irrlicht/libpng/pngpriv.h	2016-12-17 13:35:44.000000000 -0800
@@ -794,23 +794,6 @@
 #include "pngstruct.h"
 #include "pnginfo.h"
 
-/* Validate the include paths - the include path used to generate pnglibconf.h
- * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
- */
-#if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
-#  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
-      "-I (include path) error: see the notes in pngpriv.h"
-   /* This means that when pnglibconf.h was built the copy of zlib.h that it
-    * used is not the same as the one being used here.  Because the build of
-    * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
-    * zlib version number and because this affects handling of certain broken
-    * PNG files the -I directives must match.
-    *
-    * The most likely explanation is that you passed a -I in CFLAGS. This will
-    * not work; all the preprocessor directories and in particular all the -I
-    * directives must be in CPPFLAGS.
-    */
-#endif
 
 /* This is used for 16-bit gamma tables -- only the top level pointers are
  * const; this could be changed: