use macro for EXTERN "C" begin and end lines in header files to clean up the headers, and to eliminate a format bug in emacs.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@1291 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/include/switch_rtp.h

@@ -38,12 +38,7 @@
 #ifndef SWITCH_RTP_H
 #define SWITCH_RTP_H
 
-#ifdef __cplusplus
-extern "C" {
-#ifdef _FORMATBUG
-}
-#endif
-#endif
+BEGIN_EXTERN_C
 
 #define SWITCH_RTP_MAX_BUF_LEN 16384
 
@@ -328,8 +323,6 @@ SWITCH_DECLARE(void *)switch_rtp_get_private(switch_rtp *rtp_session);
   \}
 */
 
-#ifdef __cplusplus
-}
-#endif
+END_EXTERN_C
 
 #endif