[signal] Add generic signal registration and dispatch...

This will be used for generic registration and dispatching
of any kind of event. We will have different areas (like
with the debug interface) and each layer can define their
own struct for the event message... This is not tested yet
diff --git a/src/Makefile.am b/src/Makefile.am
index 2a70b8b..714fff5 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -7,7 +7,7 @@
 		gsm_subscriber.c msgb.c select.c chan_alloc.c timer.c debug.c db.c \
 		gsm_04_11.c telnet_interface.c telnet_parser.l subchan_demux.c \
 		trau_frame.c trau_mux.c paging.c e1_config.c e1_input.c tlv_parser.c \
-		input/misdn.c input/ipaccess.c
+		input/misdn.c input/ipaccess.c signal.c
 bsc_hack_LDADD = -ldl -ldbi
 
 bs11_config_SOURCES = bs11_config.c abis_nm.c gsm_data.c msgb.c debug.c select.c timer.c rs232.c