patch 9.1.0219: Vim9: No enum support

Problem:  No enum support
Solution: Implement enums for Vim9 script
          (Yegappan Lakshmanan)

closes: #14224

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/vim9class.pro b/src/proto/vim9class.pro
index 1ed175e..d3d3b99 100644
--- a/src/proto/vim9class.pro
+++ b/src/proto/vim9class.pro
@@ -3,6 +3,7 @@
 int is_valid_builtin_obj_methodname(char_u *funcname);
 ufunc_T *class_get_builtin_method(class_T *cl, class_builtin_T builtin_method, int *method_idx);
 void ex_class(exarg_T *eap);
+void enum_set_internal_obj_vars(class_T *en, object_T *enval);
 type_T *oc_member_type(class_T *cl, int is_object, char_u *name, char_u *name_end, int *member_idx);
 type_T *oc_member_type_by_idx(class_T *cl, int is_object, int member_idx);
 void ex_enum(exarg_T *eap);