Stat hack representation

	Stat hack representation
	* name-lookup.c (STAT_HACK_P, STAT_TYPE, STAT_DECL)
	MAYBE_STAT_DECL, MAYBE_STAT_TYPE): New.
	(stat_hack): New.
	(find_namespace_binding): Replace with ...
	(find_namespace_slot): ... this.
	(find_namespace_value): New.
	(name_lookup::search_namespace_only,
	name_lookup::adl_namespace_only): Adjust.
	(update_binding): Add SLOT parameter, adjust.
	(check_local_shadow): Use find_namespace_value.
	(set_local_extern_decl_linkage): Likewise.
	(do_pushdecl): Adjust for namespace slot.
	(push_local_binding): Assert not a namespace binding.
	(check_for_out_of_scope_variable): Use find_namespace_value.
	(set_identifier_type_value_with_scope): Likewise.
	(get_namespace_binding): Likewise.
	(set_namespace_binding): Delete.
	(set_global_binding): Directly update the binding.
	(finish_namespace_using_decl): Likewise.
	(lookup_type_scope_1): Use find_namespace_slot and update.
	(do_push_nested_namespace): Use find_namespace_value.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@248574 138bc75d-0d04-0410-961f-82ee72b054a4