`getopt` already prints a message on parse errors, but it still
seems like good style to point to --help as we do elsewhere.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3113>
--longoptions 'skip-mutter' \
--longoptions 'set-default' \
--longoptions 'help' \
- -- "$@")
+ -- "$@") || die "Run $(basename $0) --help to see available options"
eval set -- "$TEMP"
unset TEMP
--longoptions 'toolbox:' \
--longoptions 'dist' \
--longoptions 'help' \
- -- "$@")
+ -- "$@") || die "Run $(basename $0) --help to see available options"
eval set -- "$TEMP"
unset TEMP