* class.c (dfs_accumulate_vtbl_inits): Just point to the base we're
	sharing a ctor vtable with.  Merge code for cases 1 and 2.
	(binfo_ctor_vtable): New fn.
	(build_vtt_inits, dfs_build_secondary_vptr_vtt_inits): Use it.

From-SVN: r43399