$OpenBSD: patch-src_imageio_format_png_c,v 1.3 2012/09/14 09:50:19 sthen Exp $
--- src/imageio/format/png.c.orig	Sat Jul 21 04:44:08 2012
+++ src/imageio/format/png.c	Tue Aug 21 09:37:39 2012
@@ -28,6 +28,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <png.h>
+#include <zlib.h>
 #include <inttypes.h>
 #include <zlib.h>
 
