--- Rendering/vtkOpenGL.h.orig	2012-10-15 13:33:21.000000000 -0700
+++ Rendering/vtkOpenGL.h	2015-02-11 14:09:16.000000000 -0800
@@ -19,6 +19,7 @@
 
 // To prevent gl.h to include glext.h provided by the system
 #define GL_GLEXT_LEGACY
+#define GLX_GLXEXT_LEGACY
 #if defined(__APPLE__) && (defined(VTK_USE_CARBON) || defined(VTK_USE_COCOA))
 # include <OpenGL/gl.h> // Include OpenGL API.
 #else