Fix build against new mesa.  See:

  https://bugs.freedesktop.org/show_bug.cgi?id=83631
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=765938

Description: fixes FTBFS against new libjpeg-turbo
Author: Ondřej Surý <ondrej@debian.org>
Bug-Debian: https://bugs.debian.org/765938
Reviewed-By: Anton Gladky <gladk@debian.org>
Last-Update: 2014-10-22

Index: vtk6-6.1.0+dfsg2/Rendering/OpenGL/vtkOpenGL.h
===================================================================
--- vtk6-6.1.0+dfsg2.orig/Rendering/OpenGL/vtkOpenGL.h
+++ vtk6-6.1.0+dfsg2/Rendering/OpenGL/vtkOpenGL.h
@@ -20,6 +20,7 @@
 
 // To prevent gl.h to include glext.h provided by the system
 #define GL_GLEXT_LEGACY
+#define GLX_GLEXT_LEGACY
 #if defined(__APPLE__) && (defined(VTK_USE_CARBON) || defined(VTK_USE_COCOA))
 # include <OpenGL/gl.h> // Include OpenGL API.
 #else
Index: vtk6-6.1.0+dfsg2/Rendering/OpenGL/vtkXOpenGLRenderWindow.cxx
===================================================================
--- vtk6-6.1.0+dfsg2.orig/Rendering/OpenGL/vtkXOpenGLRenderWindow.cxx
+++ vtk6-6.1.0+dfsg2/Rendering/OpenGL/vtkXOpenGLRenderWindow.cxx
@@ -27,7 +27,7 @@
 
 // define GLX_GLXEXT_LEGACY to prevent glx.h to include glxext.h provided by
 // the system
-//#define GLX_GLXEXT_LEGACY
+#define GLX_GLXEXT_LEGACY
 #include "GL/glx.h"
 
 #include "vtkgl.h"