bug#10317: PING - bug#10317: patch to su: -l and -p should not be used together

[Voelker, Bernhard]

Jim Meyering wrote:

> I see that Fedora still uses su from coreutils, too,
> so this is a worthwhile change.

So does OpenSuSE.

As in coreutils.texi, -l and -p can be used together,
although it's not very clear what will happen:

  @item -m
  @itemx -p
  @itemx --preserve-environment
  ...
  Parts of what this option does can be
  overridden by @option{--login} and @option{--shell}.

Have a nice day,
Berny