RFC: Fix "break *EXP thread NUM"

[Maciej W. Rozycki]

On Wed, 25 Nov 2009, Daniel Jacobowitz wrote:

> > Meanwhile, here's a patch that handles "t" and "task".  I talked to
> > Andrew about this, and I still think we can get away without "+N" and
> > "-N"; they're only accepted by an accident of strtol.
> 
> I have checked this in.

 While we are at it -- it may be worth thinking about propagating thread 
information associated with breakpoints and watchpoints down to the 
respective backends.  Some processors (like the MIPS 34K multi-threaded 
core) supports thread qualification for execution and data breakpoints in 
hardware and debug stubs would be eager to make use of that for 
performance gain.  Has it been considered before?

  Maciej