png_unknown_chunkp  928 extra_lib/include/png/png.h    png_unknown_chunkp unknown_chunks;
png_unknown_chunkp 1138 extra_lib/include/png/png.h typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp));
png_unknown_chunkp 2490 extra_lib/include/png/png.h    png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));