Kill DECL_NAMESPACE_USERS, DECL_NAMESPACE_ASSOCIATIONS.

Kill DECL_NAMESPACE_USERS, DECL_NAMESPACE_ASSOCIATIONS.

	gcc/cp/
	Kill DECL_NAMESPACE_USERS, DECL_NAMESPACE_ASSOCIATIONS.
	* cp-tree.h (lang_decl_ns): Remove ns_users field.
	(DECL_NAMESPACE_USERS, DECL_NAMESPACE_ASSOCIATIONS): Delete.
	(TREE_INDIRECT_USING): Delete.
	* name-lookup.h (is_associated_namespace): Delete.
	* name-lookup.c (name_lookup::search_usings
	name_lookup::do_queue_usings): Usings are always direct.
	(is_associated_namespace): Delete.
	(handle_namespace_attrs): Use DECL_NAMESPACE_INLINE_P.
	(namespace_ancestor_1, namespace_ancestor): Delete.
	(push_using_directive_1, push_using_directive): Delete.
	(add_using_namespace_1): Delete.
	(add_using_namespace): Reimplement.
	(emit_debug_info_using_namespace): New.
	(finish_namespace_using_directive, finish_local_using_directive
	push_namespace): Adjust.
	* tree.c (cp_free_lang_data): Remove DECL_NAMESPACE_USERS
	handling.

	libcc1/
	* libcp1plugin.cc (plugin_make_namespace_inline): Check and set
	DECL_NAMESPACE_INLINE_P.

	gcc/testsuite/
	* g++.dg/lookup/using56.C: New.
	* g++.dg/lookup/using57.C: New.
	* g++.dg/lookup/using58.C: New.
	* g++.dg/lookup/using59.C: New.

From-SVN: r248467