RFC: don't call add_target for thread_db_ops

[Ulrich Weigand]

Tom Tromey wrote:

> This removes a few more erroneous calls to add_target.  These calls
> end up installing the target in a user-visible way; but these targets
> are all auto-activated and, I think, should never be explicitly
> requested.
> 
> I have no way to test these.
> 
> CCing Ulrich for the SPU case.

Makes sense to me.

Thanks,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com