readlink: support --, -n always

POSIX will be standardizing readlink (just the -n option) and realpath
(just -E and -e options):
https://www.austingroupbugs.net/view.php?id=1457

Change things for readlink so that the POSIX-mandated -n and -- work
even when disabling the non-standard (and partially non-working) -f
when FEATURE_READLINK_FOLLOW is clear.

POSIX also wants readlink to be verbose by default (if the argument is
not a symlink, readlink must output a diagnostic); I did NOT address
that one, because I'm waiting to see what the GNU Coreutils folks do:
https://lists.gnu.org/archive/html/bug-coreutils/2023-03/msg00035.html

Partial fix for https://bugs.busybox.net/show_bug.cgi?id=15466

function                                             old     new   delta
packed_usage                                       34538   34557     +19

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

0 files changed, 0 insertions, 0 deletions