File r38/lisp/csl/support-packages/README.config.guess artifact ebc88af96b part of check-in b5833487d7

The file "config.guess" identifies the machine that it is run on,
returning a GNU-style triple, eg i686-pc-linux. While the file is
licensed under the GPL it comes with a special exception whereby it can
be propagated under other licenses provided it accompanies a program
that uses the GNU autoconf mechanisms. Both FOX and CSL use autoconf, and
so between them they clearly allow this file to be distributed here along
with them.