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_module_interfaces.h

@@ -39,12 +39,10 @@
 #ifndef SWITCH_MODULE_INTERFACES_H
 #define SWITCH_MODULE_INTERFACES_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #include <switch.h>
 
+BEGIN_EXTERN_C
+
 /*! \brief A table of functions to execute at various states 
 */
 struct switch_state_handler_table {
@@ -513,8 +511,6 @@ struct switch_api_interface {
 	const struct switch_api_interface *next;
 };
 
-#ifdef __cplusplus
-}
-#endif
+END_EXTERN_C
 
 #endif