Environment: Ubuntu 20.04, uutils main branch (git commit 88cdf16), GNU coreutils v9.5.227-28b1

Steps to reproduce:

env kill -l -s 1

What I expected to happen: GNU kill forbids combining -l and -s options:

kill: cannot combine signal with -l or -t
Try 'kill --help' for more information.

What happens now: uutils kill ignores the -s argument, listing the signals:

HUP
INT
QUIT
# etc.

Notes: this is causing a failure in the GNU test file tests/misc/kill.sh.