Add version-specific defines for each C interface.

ppapi/c/dev/ppb_font_dev.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_DEV_PPB_FONT_DEV_H_
 #define PPAPI_C_DEV_PPB_FONT_DEV_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/pp_var.h"
 
-#define PPB_FONT_DEV_INTERFACE "PPB_Font(Dev);0.5"
+#define PPB_FONT_DEV_INTERFACE_0_5 "PPB_Font(Dev);0.5"
+#define PPB_FONT_DEV_INTERFACE PPB_FONT_DEV_INTERFACE_0_5
 
 struct PP_Point;
 struct PP_Rect;
 
 typedef enum {
   // Uses the user's default web page font (normally either the default serif
   // or sans serif font).
   PP_FONTFAMILY_DEFAULT = 0,
 
   // These families will use the default web page font corresponding to the
@@ skipping 146 matching lines @@
   // placed at the given position. This handles complex scripts such as Arabic,
   // where characters may be combined or replaced depending on context. Returns
   // -1 on error.
   int32_t (*PixelOffsetForCharacter)(PP_Resource font,
                                      const struct PP_TextRun_Dev* text,
                                      uint32_t char_offset);
 };
 
 #endif  /* PPAPI_C_DEV_PPB_FONT_DEV_H_ */