VORBIS_DLL - Only if building with sound on Windows; paths to vorbis DLLs
VORBIS_INCLUDE_DIR - Only if building with sound; directory that contains a directory vorbis with vorbisenc.h inside
VORBIS_LIBRARY - Only if building with sound; path to libvorbis.a/libvorbis.so/libvorbis.dll.a
- XXF86VM_LIBRARY - Only on Linux; path to libXXf86vm.a/libXXf86vm.so
ZLIB_DLL - Only on Windows; path to zlib1.dll
ZLIB_INCLUDE_DIR - Directory that contains zlib.h
ZLIB_LIBRARY - Path to libz.a/libz.so/zlib.lib