Add version-specific defines for each C interface.

ppapi/c/ppb_graphics_2d.h

 /* Copyright (c) 2010 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef PPAPI_C_PPB_GRAPHICS_2D_H_
 #define PPAPI_C_PPB_GRAPHICS_2D_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_module.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 
 struct PP_CompletionCallback;
 struct PP_Point;
 struct PP_Rect;
 struct PP_Size;
 
-#define PPB_GRAPHICS_2D_INTERFACE "PPB_Graphics2D;0.3"
+#define PPB_GRAPHICS_2D_INTERFACE_0_3 "PPB_Graphics2D;0.3"
+#define PPB_GRAPHICS_2D_INTERFACE PPB_GRAPHICS_2D_INTERFACE_0_3
 
 /**
  * @file
  * Defines the PPB_Graphics2D struct.
  *
  * @addtogroup Interfaces
  * @{
  */
 
 /** {PENDING: describe PPB_Graphics2D. */
@@ skipping 194 matching lines @@
   int32_t (*Flush)(PP_Resource graphics_2d,
                    struct PP_CompletionCallback callback);
 
 };
 
 /**
  * @}
  */
 #endif  /* PPAPI_C_PPB_GRAPHICS_2D_H_ */