[Lazarus] Error SIGILL appearing out of the blue, what does it mean?

[Bo Berglund]

Yesterday I was testing lnet and the test project was working just
fine. Today I came back and hit run again only to find a pop-up error
box saying:
Project xxx raised exception class 'External: SIGILL'."

I have restarted Lazarus and even made a Build Clean but the problem
persists. I don't even get to keep what has been written to the
console (I see a few lines appearing but they are immediately erased).
Yesterday whatever was written to the console remained until the test
program was started again. That was very convenient in order to trace
what happened against the source.

Where should I look for a solution to this?


-- 
Bo Berglund
Developer in Sweden