diff --git a/programs/services/tests/service.c b/programs/services/tests/service.c
index 0e9bcd7486f..98419497a5a 100644
--- a/programs/services/tests/service.c
+++ b/programs/services/tests/service.c
@@ -16,6 +16,8 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#include <stdarg.h>
+
 #include <windef.h>
 #include <winsvc.h>
 #include <stdio.h>