png_hIST          111 contrib/libtests/pngunknown.c #define png_hIST PNG_U32(104,  73,  83,  84)
png_hIST          120 contrib/tools/pngfix.c #define png_hIST PNG_U32(104,  73,  83,  84)
png_hIST          763 pngpriv.h      #define png_hIST PNG_U32(104,  73,  83,  84)