diff --git a/Configurations/10-main.conf b/Configurations/10-main.conf
index cc1a207ea8..4a2abaeb3a 100644
--- a/Configurations/10-main.conf
+++ b/Configurations/10-main.conf
@@ -1730,7 +1730,7 @@ sub vms_info {
         lflags           => picker(default => "/MAP",
                                    debug   => "/DEBUG/TRACEBACK",
                                    release => "/NODEBUG/NOTRACEBACK"),
-        lib_cflags       => add("/NAMES=(AS_IS,SHORTENED)"),
+        lib_cflags       => add("/NAMES=(AS_IS,SHORTENED)/EXTERN_MODEL=STRICT_REFDEF"),
         dso_cflags       => add("/NAMES=(AS_IS,SHORTENED)"),
         shared_target    => "vms-shared",
         dso_scheme       => "vms",