[cogl] buffer: make the COGL_BUFFER casting macro public

[Robert Bragg <rbragg src gnome org>]

commit f3a4d211875894cf7081a3f93049fccdaaea7dcf
Author: Robert Bragg <robert linux intel com>
Date:   Wed Aug 3 15:50:14 2011 +0100

    buffer: make the COGL_BUFFER casting macro public
    
    The CoglBuffer api is available as experimental 2.0 api but we forgot to
    exposed the COGL_BUFFER casting macro.
    
    Reviewed-by: Neil Roberts <neil linux intel com>

 cogl/cogl-buffer-private.h |    2 --
 cogl/cogl-buffer.h         |    2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/cogl/cogl-buffer-private.h b/cogl/cogl-buffer-private.h
index c601f79..ed324f9 100644
--- a/cogl/cogl-buffer-private.h
+++ b/cogl/cogl-buffer-private.h
@@ -36,8 +36,6 @@
 
 G_BEGIN_DECLS
 
-#define COGL_BUFFER(buffer)     ((CoglBuffer *)(buffer))
-
 typedef struct _CoglBufferVtable CoglBufferVtable;
 
 struct _CoglBufferVtable
diff --git a/cogl/cogl-buffer.h b/cogl/cogl-buffer.h
index f3b3dbc..800702e 100644
--- a/cogl/cogl-buffer.h
+++ b/cogl/cogl-buffer.h
@@ -74,6 +74,8 @@ G_BEGIN_DECLS
 #define cogl_buffer_unmap cogl_buffer_unmap_EXP
 #define cogl_buffer_set_data cogl_buffer_set_data_EXP
 
+#define COGL_BUFFER(buffer)     ((CoglBuffer *)(buffer))
+
 typedef struct _CoglBuffer CoglBuffer;
 
 /**