$OpenBSD: patch-src_pngio_c,v 1.1.1.1 2011/12/22 09:46:46 ajacoutot Exp $
--- src/pngio.c.orig	Wed Dec 21 19:37:12 2011
+++ src/pngio.c	Wed Dec 21 19:37:37 2011
@@ -98,6 +98,9 @@
 #include <string.h>
 #include "allheaders.h"
 
+/* Z_DEFAULT_COMPRESSION */
+#include <zlib.h>
+
 #ifdef HAVE_CONFIG_H
 #include "config_auto.h"
 #endif  /* HAVE_CONFIG_H */