[mutter] Define new tokens from the ARB_robustness extension if needed

[Mario Sanchez Prada <msanchez src gnome org>]

commit e435cf301f78971f3d4965468f53ccad7ab1b2f8
Author: Mario Sanchez Prada <mario endlessm com>
Date:   Mon Apr 17 12:21:16 2017 +0100

    Define new tokens from the ARB_robustness extension if needed
    
    The ARB_robustness extension defined the following tokens as
    returned by GetGraphicsResetStatusARB (see spec at [1]):
    
      GUILTY_CONTEXT_RESET_ARB    0x8253
      INNOCENT_CONTEXT_RESET_ARB  0x8254
      UNKNOWN_CONTEXT_RESET_ARB   0x8255
    
    These tokens might not be defined in some GL implementations,
    such as Mesa 13's implementation of GLES 2.0, so we need to
    define them ourselves not to break those builds.
    
    [1] https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_robustness.txt
    
    https://bugzilla.gnome.org/show_bug.cgi?id=781398

 cogl/cogl/cogl-context.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)
---
diff --git a/cogl/cogl/cogl-context.c b/cogl/cogl/cogl-context.c
index c45c9b4..70d2206 100644
--- a/cogl/cogl/cogl-context.c
+++ b/cogl/cogl/cogl-context.c
@@ -81,6 +81,19 @@
 #define GL_PURGED_CONTEXT_RESET_NV 0x92BB
 #endif
 
+/* These aren't defined in the GLES2 headers */
+#ifndef GL_GUILTY_CONTEXT_RESET_ARB
+#define GL_GUILTY_CONTEXT_RESET_ARB 0x8253
+#endif
+
+#ifndef GL_INNOCENT_CONTEXT_RESET_ARB
+#define GL_INNOCENT_CONTEXT_RESET_ARB 0x8254
+#endif
+
+#ifndef GL_UNKNOWN_CONTEXT_RESET_ARB
+#define GL_UNKNOWN_CONTEXT_RESET_ARB 0x8255
+#endif
+
 static void _cogl_context_free (CoglContext *context);
 
 COGL_OBJECT_DEFINE (Context, context);