diff -ruN FreeCAD-0.12.5284.orig/src/Mod/Image/Gui/GLImageBox.cpp FreeCAD-0.12.5284/src/Mod/Image/Gui/GLImageBox.cpp
--- FreeCAD-0.12.5284.orig/src/Mod/Image/Gui/GLImageBox.cpp	2012-01-03 13:24:30.000000000 +0100
+++ FreeCAD-0.12.5284/src/Mod/Image/Gui/GLImageBox.cpp	2012-01-06 10:26:38.000000000 +0100
@@ -27,6 +27,8 @@
 # include <GL/glext.h>
 #endif
 
+#include <GL/glu.h>
+
 #include "GLImageBox.h"
 
 using namespace ImageGui;