diff --git a/libs/freetdm/src/ftmod/ftmod_sangoma_boost/sangoma_boost_client.c b/libs/freetdm/src/ftmod/ftmod_sangoma_boost/sangoma_boost_client.c
index 982dd4794d..6ddb74d253 100644
--- a/libs/freetdm/src/ftmod/ftmod_sangoma_boost/sangoma_boost_client.c
+++ b/libs/freetdm/src/ftmod/ftmod_sangoma_boost/sangoma_boost_client.c
@@ -31,6 +31,8 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#define _GNU_SOURCE
+
 #if HAVE_NETDB_H
 #include <netdb.h>
 #endif