[cogl] Add COGL_HAS_GL and COGL_HAS_GLES

Cogl already add similar defines but with the CLUTTER namespace
(CLUTTER_COGL_HAS_GL and CLUTTER_COGL_HAS_GLES). Let's just add two
similar defines with the COGL namespace. Removing the CLUTTER_COGL ones
could break applications silently for no real good reason.

gl/cogl-defines.h.in

@@ -685,6 +685,7 @@ G_BEGIN_DECLS
 #define CGL_OBJECT_COMPILE_STATUS  GL_OBJECT_COMPILE_STATUS_ARB
 
 #define CLUTTER_COGL_HAS_GL 1
+#define COGL_HAS_GL 1
 
 /* Extension function prototypes */
 

gles/cogl-defines.h.in

@@ -448,6 +448,7 @@ G_BEGIN_DECLS
 #endif
 
 #define CLUTTER_COGL_HAS_GLES 1
+#define COGL_HAS_GLES 1
 
 /* These aren't always defined under GLES 2 but if they are then we
    should probably use the GL_* macro instead of assuming the