gprs_ns.c: Make make_socket known to the compiler
diff --git a/openbsc/src/gprs/gprs_ns.c b/openbsc/src/gprs/gprs_ns.c
index 467e43a..4846b64 100644
--- a/openbsc/src/gprs/gprs_ns.c
+++ b/openbsc/src/gprs/gprs_ns.c
@@ -69,6 +69,7 @@
 #include <openbsc/signal.h>
 #include <openbsc/gprs_ns.h>
 #include <openbsc/gprs_bssgp.h>
+#include <openbsc/socket.h>
 
 static const struct tlv_definition ns_att_tlvdef = {
 	.def = {