extern bool require_potential_rvalue_constant_expression (tree);
extern tree cxx_constant_value (tree, tree = NULL_TREE);
extern tree cxx_constant_init (tree, tree = NULL_TREE);
-extern tree maybe_constant_value (tree, tree = NULL_TREE);
+extern tree maybe_constant_value (tree, tree = NULL_TREE, bool = false);
extern tree maybe_constant_init (tree, tree = NULL_TREE, bool = false);
extern tree fold_non_dependent_expr (tree, tsubst_flags_t = tf_warning_or_error);
extern tree fold_simple (tree);