[RFA] Implement thread death notification.

[Daniel Jacobowitz]

On Sat, Apr 26, 2008 at 08:21:50PM +0300, Vladimir Prus wrote:
> 
> We now have the 'thread-created' MI notification. This patch adds a
> 'thread-exited' notification to match. Are non-MI bits of this
> patch OK?

No, I don't think this is good enough.  It's "thread has exited but
only if the target is native GNU/Linux".  While for some targets we
will not detect thread exit until "info threads", which is
unfortunate, at least the code to call the observer should be in
generic code.  Can't we call it from delete_thread?

Also, please do not commit without documentation for the notification.

-- 
Daniel Jacobowitz
CodeSourcery