$NetBSD: patch-al,v 1.1 2011/01/17 17:57:01 jnemeth Exp $

--- src/pngoutput.c.orig	2003-09-26 18:07:41.000000000 +0000
+++ src/pngoutput.c
@@ -19,6 +19,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <png.h>
+#include <zlib.h>
 #include "pngoutput.h"
 
 struct pngoutput_s