* search.c (dfs_search, binfo_for_vtable, dfs_bfv_helper): New fns.
	* decl2.c (output_vtable_inherit): Call binfo_for_vtable.
	* lang-options.h: Add -fvtable-gc.
	* cp-tree.h: Add flag_vtable_gc.
	* decl2.c (output_vtable_inherit): New fn.
	(finish_vtable_vardecl): Call it.
	* class.c (build_vtable_entry_ref): New fn.
	(build_vtbl_ref): Call it.

From-SVN: r22061