Re: make-stds.texi minor update

[Karl Berry]

            * doc/make-stds.texi: Bump copyright year.
            (Command Variables, Directory Variables): Fix spelling
            `filesystem' -> `file system'.

Got the ok from rms to apply this change (and to apply future typo-like
patches myself without bothering him, yay for that).  So I changed it in
gnustandards and gnulib.

Thanks,
Karl