First batch of changes required for MacOS X build. Orignal submission from

Phil Atkin, merged by Robert Osfield.

include/osg/GL

@@ -9,7 +9,7 @@
 
     // non windows, doesn't require nonsense as seen below :-)    
     #ifndef __gl_h_
-        #ifdef __APPLE_CC__
+        #ifdef __DARWIN_OSX__
             #include <OpenGL/gl.h>
         #else
 	    #include <GL/gl.h>

include/osg/GLU

@@ -5,7 +5,7 @@
 #ifndef OSG_GLU
 #define OSG_GLU 1
 
-#ifdef __APPLE_CC__
+#ifdef __DARWIN_OSX__
 	#include <OpenGL/glu.h>
 #else
 	#include <GL/glu.h>

include/osg/Timer

@@ -33,7 +33,7 @@ class SG_EXPORT Timer {
         Timer();
         ~Timer() {}
 
-	#if defined __APPLE__  || defined macintosh
+	#if defined __DARWIN_OSX__  || defined macintosh
 	// PJA MAC OSX - inline Tick() pollutes namespace so badly 
 	// we cant compile, due to Carbon.h ...
         Timer_t tick();
@@ -150,7 +150,7 @@ namespace osg{
     }
 };
 
-#elif !defined (__APPLE_CC__) && !defined (macintosh)
+#elif !defined (__DARWIN_OSX__) && !defined (macintosh)
 
     // no choice, always use std::clock()