Linux config.guess overhaul

[Ben Elliston]

After much pondering on how to best solve the much-needed cleanup for Linux
detection in config.guess, I have made a start.  Some of the grossness will
remain with us for some time until I can be sure that there will be very few
users on certain systems--such as a.out SPARC Linux.

In the meantime, the development version of config.guess is in
subversions.gnu.org's CVS repository on the linux-overhaul-20010122 branch.
I have made a rough first pass at this today, although some systems have
been intentionally omitted until I receive necessary information.

Please try it out and report on failures so I can add support for those
systems.  Thanks,

Ben