png-1.5 defines PNG_CALLBACK as well, so rename our PNG_CALLBACK
-rw-r--r-- 1310 CMakeLists.txt
drwxr-xr-x - Example
-rw-r--r-- 978 Makefile
drwxr-xr-x - cmake
-rw-r--r-- 14641 glpng.htm
drwxr-xr-x - include
drwxr-xr-x - src