[cogl] misc: Add the single include guard to cogl-define.h

[Damien Lespiau <dlespiau src gnome org>]

commit 051e6da8875b9547a3b2281be2f6c25071653b3d
Author: Damien Lespiau <damien lespiau intel com>
Date:   Fri May 13 08:11:57 2011 +0100

    misc: Add the single include guard to cogl-define.h
    
    This is a generated file and maybe the reason why it was not included
    the first time?

 cogl/cogl-defines.h.in |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/cogl/cogl-defines.h.in b/cogl/cogl-defines.h.in
index 0803463..5baa3b9 100644
--- a/cogl/cogl-defines.h.in
+++ b/cogl/cogl-defines.h.in
@@ -21,6 +21,10 @@
  *
  */
 
+#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
+#error "Only <cogl/cogl.h> can be included directly."
+#endif
+
 #ifndef __COGL_DEFINES_H__
 #define __COGL_DEFINES_H__