diff --git a/mbuni/mmsc/mmsc.c b/mbuni/mmsc/mmsc.c
index 4e9fd99..da77140 100644
--- a/mbuni/mmsc/mmsc.c
+++ b/mbuni/mmsc/mmsc.c
@@ -10,7 +10,7 @@
  * This program is free software, distributed under the terms of
  * the GNU General Public License, with a few exceptions granted (see LICENSE)
  */
-
+#include <signal.h>
 #include "mmsc.h"
 #include "mms_uaprof.h"