add gsup_test_client program

Related: OS#1592
Change-Id: Iafd844393dd90b899f84ed61c875c1eb533436d7
diff --git a/openbsc/src/gprs/gprs_gsup_client.c b/openbsc/src/gprs/gprs_gsup_client.c
index a4aca09..deaf156 100644
--- a/openbsc/src/gprs/gprs_gsup_client.c
+++ b/openbsc/src/gprs/gprs_gsup_client.c
@@ -25,6 +25,7 @@
 #include <osmocom/abis/ipa.h>
 #include <osmocom/gsm/protocol/ipaccess.h>
 #include <osmocom/core/msgb.h>
+#include <osmocom/core/logging.h>
 
 #include <openbsc/debug.h>