Add SGs Interface

Add an SGs interface (3GPP TS 29.118) to osmo-msc in order to support
SMS tunneling and Circuit Switched Fallback (CSFB)

Change-Id: I73359925fc1ca72b33a1466e6ac41307f2f0b11d
Related: OS#3615
diff --git a/src/libvlr/Makefile.am b/src/libvlr/Makefile.am
index dcae1c7..14cd302 100644
--- a/src/libvlr/Makefile.am
+++ b/src/libvlr/Makefile.am
@@ -8,6 +8,7 @@
 	   $(LIBOSMOGSUPCLIENT_CFLAGS) \
 	   $(LIBOSMOABIS_CFLAGS) \
 	   $(LIBOSMORANAP_CFLAGS) \
+	   $(LIBOSMOGSM_CFLAGS) \
 	   $(COVERAGE_CFLAGS) \
 	   $(NULL)
 
@@ -16,6 +17,7 @@
 	vlr_auth_fsm.h \
 	vlr_core.h \
 	vlr_lu_fsm.h \
+	vlr_sgs_fsm.h \
 	$(NULL)
 
 noinst_LIBRARIES = libvlr.a
@@ -25,4 +27,6 @@
 	vlr_access_req_fsm.c \
 	vlr_auth_fsm.c \
 	vlr_lu_fsm.c \
+	vlr_sgs.c \
+	vlr_sgs_fsm.c \
 	$(NULL)