Previously Signal.signal returned SIG_DFL unless a signal had been set and even if the surrounding context had set it to SIG_IGN.  Now determines the signal settings at start-up. Also the default Poly ctrl-C handler is treated as a SIG_HANDLER with a special value instead of SIG_DFL.  That allows Signal.signal to set it to SIG_DFL with its normal meaning of killing the process.
Previously Signal.signal returned SIG_DFL unless a signal had been set and even if the
surrounding context had set it to SIG_IGN.  Now determines the signal settings at start-up.
Also the default Poly ctrl-C handler is treated as a SIG_HANDLER with a special value instead of
SIG_DFL.  That allows Signal.signal to set it to SIG_DFL with its normal meaning of killing the process.


git-svn-id: 98787b36aaefbae4b30fa755be920954cd25e1e4@396 ae7d391e-3f74-4a2b-a0db-a8776840fd2a

dcjm/polyml,dcjm/polyml,dcjm/polyml,polyml/polyml,mn200/polyml,polyml/polyml,dcjm/polyml,polyml/polyml,mn200/polyml,mn200/polyml,polyml/polyml,mn200/polyml