Include GLU directly in FTGL instead via glew.h

This is part of the glew replacement campaign.

Author: guitargeek

graf3d/ftgl/CMakeLists.txt

@@ -40,7 +40,6 @@ ROOT_LINKER_LIBRARY(FTGL
     OpenGL::GLU
     ${FREETYPE_LIBRARIES}
     ZLIB::ZLIB
-    GLEW::GLEW
   BUILTINS
     FREETYPE
 )

graf3d/ftgl/inc/FTGL.h

@@ -22,7 +22,11 @@ typedef float    FTGL_FLOAT;
 #include "Windows4Root.h"
 #endif
 
-#include <GL/glew.h>
+#ifdef __APPLE__
+#include <OpenGL/glu.h>
+#else
+#include <GL/glu.h>
+#endif
 
 #ifndef WIN32
     // Required for compatibility with glext.h style function definitions of