Add version-specific defines for each C interface.

ppapi/c/dev/ppb_find_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_FIND_DEV_H_
 #define PPAPI_C_DEV_PPB_FIND_DEV_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_stdint.h"
 
-#define PPB_FIND_DEV_INTERFACE "PPB_Find(Dev);0.3"
+#define PPB_FIND_DEV_INTERFACE_0_3 "PPB_Find(Dev);0.3"
+#define PPB_FIND_DEV_INTERFACE PPB_FIND_DEV_INTERFACE_0_3
 
 struct PPB_Find_Dev {
   // Updates the number of find results for the current search term.  If
   // there are no matches 0 should be passed in.  Only when the plugin has
   // finished searching should it pass in the final count with finalResult set
   // to PP_TRUE.
   void (*NumberOfFindResultsChanged)(PP_Instance instance,
                                      int32_t total,
                                      PP_Bool final_result);
 
   // Updates the index of the currently selected search item.
   void (*SelectedFindResultChanged)(PP_Instance instance,
                                     int32_t index);
 
 };
 
 #endif  /* PPAPI_C_DEV_PPB_FIND_DEV_H_ */