Ahoy Alan,

I tested & committed your fixes and also added the multiprocessing functions to swank-opencml.lisp. Seems to work with OpenMCL 0.14-031018 on OSX.

Following onto my previous message, if I do get a debugger, when I execute sldb-quit I get another error: Can't throw to tag SWANK::SLIME-TOPLEVEL

Yeah, the new threads don't have any restarts / catch tags that we know about, and there's no slime-toplevel to return to. In OpenMCL they don't seem to have any restarts at all by default (in CMUCL there is a `destroy' restart at the top to kill off the thread).

I'm not sure of the right fix. Should we add some extra restarts somewhere in these new threads so that 'q' and 'a' in *sldb* buffers do something meaningful?