diff --git a/src/os_vms_conf.h b/src/os_vms_conf.h
index 0064608..2ede37d 100644
--- a/src/os_vms_conf.h
+++ b/src/os_vms_conf.h
@@ -106,6 +106,7 @@
 #define HAVE_FSYNC
 #define HAVE_GETPWUID
 #define HAVE_GETPWNAM
+#define HAVE_STDARG_H
 #define	HAVE_STDLIB_H
 #define	HAVE_STRING_H
 #define	HAVE_ERRNO_H