--- exp-gfx.c.orig	2012-06-26 19:33:23.000000000 +0200
+++ exp-gfx.c.orig	2012-06-26 19:34:01.000000000 +0200
@@ -137,6 +137,7 @@ 
 
 #ifdef WITH_PNG
 
+#include <zlib.h>
 #include <png.h>
 static int png_open(struct export *e);
 static int png_option(struct export *e, int opt, char *arg);