hugs w/ cygwin

[Sigbjorn Finne]

FYI, hugs builds cleanly with two cygwin installs
I've tested on here: an older one  w/ gcc-2.95
and one w/ gcc-3.2 (from a clean cygwin install
done on 29/07/03). The reported behaviour suggests
a C compiler making life too hard for the conservative
GC; one way to find out is to cut back on the use of -O2.

Re: Registry gibberish -- this was due to unhygienic macro
usage in opts.c. Fixed now.

--sigbjorn