File graphviz-gd_png_check_sig.patch of Package graphviz

--- lib/gd/gd_png.c
+++ lib/gd/gd_png.c
@@ -150,7 +150,7 @@
 	return NULL;
   }
 
-	if (!png_check_sig (sig, 8)) { /* bad signature */
+	if (png_sig_cmp (sig, 0, 8)) { /* bad signature */
     	return NULL;		/* bad signature */
 	}