Integrated changes for MacOSX, submitted by Phil Atkin, with small mods by

Robert Osfield to maintain compatability under Linux.

src/osgUtil/Tesselator.cpp

@@ -1,10 +1,9 @@
 #include <osg/GL>
+#include <osg/GLU>
+
 #include <osg/Notify>
 #include <osgUtil/Tesselator>
 
-#include <GL/glu.h>
-
-
 using namespace osg;
 using namespace osgUtil;