Implement C++0x unrestricted unions (N2544)
	* class.c (check_field_decl): Loosen union handling in C++0x.
	* method.c (walk_field_subobs): Split out from...
	(synthesized_method_walk): ...here.  Set msg before loops.
	(process_subob_fn): Check for triviality in union members.
	* init.c (sort_mem_initializers): Splice out uninitialized
	anonymous unions and union members.
	(push_base_cleanups): Don't automatically destroy anonymous unions
	and union members.

From-SVN: r162187