misc: Firs round of fixing compilation of test cases

Next round should be using them again
diff --git a/openbsc/tests/channel/Makefile.am b/openbsc/tests/channel/Makefile.am
index 5a3477c..6b7468c 100644
--- a/openbsc/tests/channel/Makefile.am
+++ b/openbsc/tests/channel/Makefile.am
@@ -10,6 +10,7 @@
 	$(top_srcdir)/src/timer.c \
 	$(top_srcdir)/src/select.c \
 	$(top_srcdir)/src/talloc.c \
-	$(top_srcdir)/src/gsm_data.c
+	$(top_srcdir)/src/gsm_data.c \
+	$(top_srcdir)/src/signal.c
 channel_test_LDADD = -ldl -ldbi
 
diff --git a/openbsc/tests/channel/channel_test.c b/openbsc/tests/channel/channel_test.c
index ab165c7..4dcf69a 100644
--- a/openbsc/tests/channel/channel_test.c
+++ b/openbsc/tests/channel/channel_test.c
@@ -74,4 +74,5 @@
 
 void nm_state_event() {}
 void input_event() {}
+void sms_alloc() {}