diff -r de3e9ea18f56 -r 3b3257a410fe src/pixmap.cc
--- a/src/pixmap.cc	Mon Sep 08 20:14:24 2014 +0200
+++ b/src/pixmap.cc	Tue Jul 26 17:41:36 2016 +0200
@@ -31,6 +31,7 @@
 
 #ifdef HAVE_PNG
 #	include <png.h>
+#   include <zlib.h>
 #endif
 
 unsigned char *Pixmap::getCharData() const