PNG_WROTE_tIME    893 pngset.c              (png_ptr->mode & PNG_WROTE_tIME))
PNG_WROTE_tIME    268 pngwrite.c           png_ptr->mode |= PNG_WROTE_tIME;
PNG_WROTE_tIME    371 pngwrite.c               !(png_ptr->mode & PNG_WROTE_tIME))