1 files changed, 1 insertions, 0 deletions
diff --git a/internal.h b/internal.h
index 509e19a228..95ce1f0daa 100644
--- a/internal.h
+++ b/internal.h
@@ -1142,6 +1142,7 @@ extern rb_encoding OnigEncodingUTF_8;
 /* variable.c */
 size_t rb_generic_ivar_memsize(VALUE);
 VALUE rb_search_class_path(VALUE);
+VALUE rb_attr_delete(VALUE, ID);
 
 /* version.c */
 extern VALUE ruby_engine_name;