move the declaration of struct ast_channel ast_frame and ast_module

to compat.h so it is always available - hopefully this will let
us reduce the number of inclusions of channel.h and frame.h



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@89426 65c4cc65-6c06-0410-ace0-fbb531ad65f3

utils/extconf.c

@@ -1835,8 +1835,6 @@ AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
 #define ast_channel_trylock(x)		ast_mutex_trylock(&x->lock)
 #else
 
-struct ast_channel;
-
 /*! \brief Lock AST channel (and print debugging output)
 \note You need to enable DEBUG_CHANNEL_LOCKS for this function */
 int ast_channel_lock(struct ast_channel *chan);