PATCH: resume + threads + software stepping == boom

[Michael Snyder]

Daniel Jacobowitz wrote:
[extensive snipping]
> +  /* If we stopped on a breakpoint and it was not deleted, we want to continue
> +     only this thread, so we should be stepping. */

I agree with the premise -- whenever we resume at a breakpoint,
we should do a single-thread-step before inserting bps, so that 
other threads do not have a chance to run (and possibly go past
other breakpoints) while breakpoints are not inserted.

How do others feel about that premise?  I think we had 
reached that consensus at some earlier time, but it has not
been implemented (almost, but not quite).