Revert one cmake change

git-svn-id: http://www.openflipper.org/svnrepo/OpenFlipper/branches/Free@5614 383ad7c9-94d9-4d36-a494-682f7c89f535

ACG/ShaderUtils/GLSLShader.cc

@@ -20,7 +20,7 @@
 #include <sstream>
 #include <fstream>
 
-#include <GL/gl.hh>
+#include <../GL/gl.hh>
 
 #include "gldebug.h"
 #include "GLSLShader.hh"