I propose that we remove support for the following OS ports from our
source tree. They are totally dead, definitely don't work, and/or
probably no one remembers what they even were. The code just bit rots
and is in the way of future improvements.
* Dead/remove:
dgux
nextstep
sunos4
svr4
ultrix4
univel
* Dubious, but keep for now:
bsdi
irix
osf
sco
* No concern:
aix
cygwin
darwin
freebsd
hpux
linux
netbsd
openbsd
solaris
unixware
win32
