fix sysvinit compatibility for shutdown wrapper

scripts/shutdown.in

@@ -1,21 +1,29 @@
 #!@SHELL@
 
-poweroff_arg=
-while getopts :HhPr opt; do
+shutdown_arg=
+while getopts :akrhPHfFnct: opt; do
 	case "$opt" in
-		h|P) poweroff_arg=--poweroff ;;
-		H) poweroff_arg=--halt ;;
-		r) poweroff_arg=--reboot ;;
-		\?) printf "${0##*/}: invalid option ${optarg}\n" >&2
+		a) ;;
+		k) ;;
+		r) shutdown_arg=--reboot ;;
+		h) shutdown_arg=--halt ;;
+		P) shutdown_arg=--poweroff ;;
+		H) shutdown_arg=--halt ;;
+		f) ;;
+		F) ;;
+		n) ;;
+		c) ;;
+		t) ;;
+		[?]) printf "%s\n" "${0##*/}: invalid command line option" >&2
 		exit 1
 		;;
 	esac
 done
 shift $((OPTIND-1))
 
-if [ -z "${poweroff_arg}" ]; then
-	poweroff_arg=--single
+if [ -z "${shutdown_arg}" ]; then
+	shutdown_arg=--single
 fi
 
-echo @SBINDIR@/openrc-shutdown ${poweroff_arg} ${@}
-exec @SBINDIR@/openrc-shutdown ${poweroff_arg} ${@}
+echo @SBINDIR@/openrc-shutdown ${shutdown_arg} "$@"
+exec @SBINDIR@/openrc-shutdown ${shutdown_arg} "$@"