c++: RTTI accessors for modules

c++: RTTI accessors for modules

The module machinery needs to serialize tinfo types and vars by
meaning, not literally.  This adds the necessary pieces to rtti.

	gcc/cp/
	* cp-tree.h (DECL_TINFO_P): Also for TYPE_DECLs.
	(get_tinfo_decl_direct): Declare.
	(get_pseudo_tinfo_index, get_pseudo_tinfo_type): Declare.
	* rtti.c (get_tinfo_decl_direct): Externalize.
	(get_tinfo_desc): Set DECL_TINFO_P on the typedef.
	(get_pseudo_tinfo_index, get_pseudo_tinfo_type): New.