[mutter] cogl: Just define the needed GLES2 extension ourself

[Jonas Ådahl <jadahl src gnome org>]

commit 5a43cc5cf9f21252aa8c80882cf3ffef0863ed1b
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Dec 9 11:54:38 2016 +0800

    cogl: Just define the needed GLES2 extension ourself
    
    We need a GLES2 extension macro in cogl-texture-2d-gl.c, but we can't
    include GLES2/gl2ext.h because it will conflict with things in
    GL/glext.h. We can't rely on cogl including anything for us since it'd
    only include GLES2/gl2ext.h if OpenGL support was explicitly disabled.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=774891

 cogl/cogl/driver/gl/cogl-texture-2d-gl.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)
---
diff --git a/cogl/cogl/driver/gl/cogl-texture-2d-gl.c b/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
index 9a29c8f..375edcb 100644
--- a/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
+++ b/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
@@ -47,14 +47,19 @@
 #include "cogl-util-gl-private.h"
 
 #if defined (COGL_HAS_EGL_SUPPORT)
-#include "cogl-egl-defines.h"
-#  ifndef COGL_HAS_GLES2
+
 /* We need this define from GLES2, but can't include the header
    as its type definitions may conflict with the GL ones
  */
-#  define GL_TEXTURE_EXTERNAL_OES           0x8D65
-#  endif
-#endif
+#ifndef GL_OES_EGL_image_external
+#define GL_OES_EGL_image_external 1
+#define GL_TEXTURE_EXTERNAL_OES           0x8D65
+#define GL_TEXTURE_BINDING_EXTERNAL_OES   0x8D67
+#define GL_REQUIRED_TEXTURE_IMAGE_UNITS_OES 0x8D68
+#define GL_SAMPLER_EXTERNAL_OES           0x8D66
+#endif /* GL_OES_EGL_image_external */
+
+#endif /* defined (COGL_HAS_EGL_SUPPORT) */
 
 void
 _cogl_texture_2d_gl_free (CoglTexture2D *tex_2d)