restart -> "Can't attach LWP" + hang

[Michael Snyder]

On Fri, 2006-08-25 at 12:30 -0400, Daniel Jacobowitz wrote:
> On Fri, Aug 25, 2006 at 09:06:42AM -0700, David L wrote:
> > Not intentionally, but I'm pretty sure a library I've linked to is
> > spawning a thread under the covers.  I'm not sure which one.
> > Below is a list of my dependencies.  In any case, could gdb
> > detect that it's multithreaded and prevent me from inserting
> > checkpoint or restarting?
> 
> Probably, though I don't know quite how.

It's a good idea, might be as simple as querying the 
internal gdb thread list.  Maybe a good first contribution
for David L?