New signal code.

I'm looking for some poeple to try out my threading patches.  I'm only
looking for people to make sure that there have been no reversions in
signal handling.  I'm not ready for people to test out the actual
threading interfaces.

You should notice no changes in application behavior or system performance
with these patches.  Let me know how it goes..

http://www.chesapeake.net/~jroberson/thr.diff

Thanks,
Jeff