Implement anonymous structs.

Implement anonymous structs.

	* cp-tree.h (ANON_AGGR_TYPE_P): Rename from ANON_UNION_TYPE_P.
	* class.c, decl.c, decl2.c, init.c, pt.c, search.c, typeck.c: Adjust.
	* class.c (finish_struct_1): Remove redundant check for anon struct.
	* decl.c (fixup_anonymous_aggr): Renamed from fixup_anonymous_union.
	(check_tag_decl): Check for anonymous struct here.
	* decl2.c (build_anon_union_vars): Catch anon struct at file scope.
	* init.c (sort_member_init, emit_base_init): Handle getting fields
	as well as names in current_member_init_list.
	(perform_member_init): Handle getting an anon aggr.
	* method.c (do_build_assign_ref): Don't descend into anon aggrs.
	(do_build_copy_constructor): Likewise.

From-SVN: r27027