LIBPNG_WARNING_CODE  934 contrib/tools/pngfix.c       case LIBPNG_WARNING_CODE:   return "warning";
LIBPNG_WARNING_CODE  956 contrib/tools/pngfix.c       case LIBPNG_WARNING_CODE:   reason = "libpng warning:"; break;
LIBPNG_WARNING_CODE 3177 contrib/tools/pngfix.c       emit_error(file, LIBPNG_WARNING_CODE, message);