$OpenBSD: patch-src_pngio_c,v 1.2 2014/01/18 14:11:23 ajacoutot Exp $
--- src/pngio.c.orig	Sun Jan 22 19:29:15 2012
+++ src/pngio.c	Sat Jan 18 14:47:02 2014
@@ -109,6 +109,9 @@
 #include <string.h>
 #include "allheaders.h"
 
+/* Z_DEFAULT_COMPRESSION */
+#include <zlib.h>
+
 #ifdef HAVE_CONFIG_H
 #include "config_auto.h"
 #endif  /* HAVE_CONFIG_H */
