1 files changed, 1 insertions, 0 deletions
diff --git a/intern.h b/intern.h
index 8f1a78ba94..fbda2a459b 100644
--- a/intern.h
+++ b/intern.h
@@ -220,6 +220,7 @@ VALUE rb_obj_is_instance_of _((VALUE, VALUE));
 VALUE rb_obj_is_kind_of _((VALUE, VALUE));
 VALUE rb_obj_alloc _((VALUE));
 VALUE rb_obj_clone _((VALUE));
+VALUE rb_obj_dup _((VALUE));
 VALUE rb_obj_taint _((VALUE));
 VALUE rb_obj_tainted _((VALUE));
 VALUE rb_obj_untaint _((VALUE));