vty: Add option to enable osmux towards BSCs

Change-Id: I6de1be0322ddbdc115074ebb6be2598ebf6c95db
diff --git a/include/osmocom/msc/Makefile.am b/include/osmocom/msc/Makefile.am
index 9ca4c38..0d7d45c 100644
--- a/include/osmocom/msc/Makefile.am
+++ b/include/osmocom/msc/Makefile.am
@@ -28,6 +28,7 @@
 	msc_t_remote.h \
 	msub.h \
 	neighbor_ident.h \
+	osmux.h \
 	paging.h \
 	ran_conn.h \
 	ran_infra.h \