--- ./htmldoc/image.cxx.orig	2013-08-09 04:53:39.000000000 +0200
+++ ./htmldoc/image.cxx	2014-01-28 04:47:41.000000000 +0100
@@ -44,6 +44,7 @@
 }
 
 #include <png.h>	/* Portable Network Graphics (PNG) definitions */
+#include <pngpriv.h>
 
 
 /*