[Ecls-list] CVS HEAD threads and signal handling

[Matthew Mondor]

I have seen improved stability in the pthread and signaling code:

- Thread killing works nicely
- I can no longer reproduce the earlier mp:with-lock problems I
  occasionally had despite a previous fix attempt at this
- Division by zero errors are indeed now reported correctly
- Also reported correctly are the segfaults for (symbol-function nil)

Thanks for the great work :)

However, an issue I still see is an endless loop when ECL receives a
SIGINT (SIGTERM works fine and causes ECL to terminate).
-- 
Matt