"su" command/docs cleanup

[Paul Rubin]

The appended doc excerpt is from "info su".  I think it's there for
historical reasons.  Contention over admin privileges on timesharing
systems like in the old days just doesn't seem to exist any more, now
that every nerd who could care about such a thing has several
computers of their very own.  

So I think this part of the doc can be removed, and the "su" program
should be made POSIX-conformant if it currently isn't.  That is, if
"su" is supposed to check for membership in a wheel group, then it
should do so.

======================================================================

       `su' can optionally be compiled to use `syslog' to report failed,
    and optionally successful, `su' attempts.  (If the system supports
    `syslog'.)  However, GNU `su' does not check if the user is a member of
    the `wheel' group; see below.

    ...

    Why GNU `su' does not support the `wheel' group
    ===============================================

       (This section is by Richard Stallman.)

       Sometimes a few of the users try to hold total power over all the
    rest.  For example, in 1984, a few users at the MIT AI lab decided to
    seize power by changing the operator password on the Twenex system and
    keeping it secret from everyone else.  (I was able to thwart this coup
    and give power back to the users by patching the kernel, but I wouldn't
    know how to do that in Unix.)

       However, occasionally the rulers do tell someone.  Under the usual
    `su' mechanism, once someone learns the root password who sympathizes
    with the ordinary users, he or she can tell the rest.  The "wheel
    group" feature would make this impossible, and thus cement the power of
    the rulers.

       I'm on the side of the masses, not that of the rulers.  If you are
    used to supporting the bosses and sysadmins in whatever they do, you
    might find this idea strange at first.