Fix most compiler warnings with gcc-4.9.2
diff --git a/openbsc/src/osmo-nitb/bsc_hack.c b/openbsc/src/osmo-nitb/bsc_hack.c
index 753fd88..3517899 100644
--- a/openbsc/src/osmo-nitb/bsc_hack.c
+++ b/openbsc/src/osmo-nitb/bsc_hack.c
@@ -50,6 +50,7 @@
 #include <osmocom/ctrl/ports.h>
 #include <openbsc/ctrl.h>
 #include <openbsc/osmo_bsc_rf.h>
+#include <openbsc/smpp.h>
 
 #include "../../bscconfig.h"