RFA: makes darwin-nat.c threads (and multi-processes) aware

[Joel Brobecker]

Hi Tristan,

> at AdaCore we have an improved version of darwin-nat.[ch] that is in
> use for a few months.  It is mostly rewritten to handle threads and
> multi-processes.  It also handles more corner cases in breakpoints
> handling.

I think you'll probably need to regenerate this patch, because of
a recent patch that I just approved which changes all instances of
strerror into safe_strerror. See:

http://www.sourceware.org/ml/gdb-patches/2009-03/msg00509.html

I hope it's not going to be too much trouble doing so. I suggest,
though, that you hold off on the re-generation until someone has had
the time to review this patch.  Might as well combine all the changes
together in one session...

-- 
Joel