cp-tree.h (cp_free_lang_data): Add extern.

	* cp-tree.h (cp_free_lang_data): Add extern.
	(ovl_skip_hidden, is_overloaded_fn, really_overloaded_fn): Add
	ATTRIBUTE_PURE.
	(type_unknown_p): Return bool, make inline, lose TREE_LIST check.
	* typeck.c (type_unknown_p): Delete.
	* tree.c (is_overloaded_fn): Use MAYBE_BASELINE_FUNCTIONS, adjust
	overload management.
	(dependent_name): Likewise.
	(decl_anon_ns_mem_p): Simplify.

From-SVN: r248433