* gdk-pixbuf-io.c (pixbuf_check_xbm): Accept xbms starting
	with a C comment - those seem to be not uncommon, e.g. the Gimp
	produces them.  (#82706)

	* io-xbm.c (read_bitmap_file_data): Don't leak memory on certain
	invalid inputs.
	(gdk_pixbuf__xbm_image_load_real): Don't leak memory on valid inputs.