make sure we build (even if not use) subchan_demux and trau_frame code

diff --git a/src/Makefile.am b/src/Makefile.am
index b0e29ee..0e200c3 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,5 +5,6 @@
 
 bsc_hack_SOURCES = bsc_hack.c misdn.c abis_rsl.c abis_nm.c gsm_04_08.c gsm_data.c \
 		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
+		gsm_04_11.c telnet_interface.c telnet_parser.l subchan_demux.c \
+		trau_frame.c
 bsc_hack_LDADD = -ldl -ldbi