Make it easy to install ly on runit systems e.g. void (#431)

* Make it easy to install ly on runit systems e.g. void

* Tidy up runit section in readme

Co-authored-by: Daniel Haarhoff <daniel@rknt.de>

res/ly-runit-service/conf

@@ -0,0 +1,14 @@
+if [ -x /sbin/agetty -o -x /bin/agetty ]; then
+	# util-linux specific settings
+	if [ "${tty}" = "tty1" ]; then
+		GETTY_ARGS="--noclear"
+	fi
+fi
+
+BAUD_RATE=38400
+TERM_NAME=linux
+
+StandardInput=tty
+TTYPath=/dev/tty2
+TTYReset=yes
+TTYVHangup=yes

res/ly-runit-service/finish

@@ -0,0 +1,3 @@
+#!/bin/sh
+tty=${PWD##*-}
+exec utmpset -w $tty

res/ly-runit-service/run

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+tty=${PWD##*-}
+
+[ -r conf ] && . ./conf
+
+if [ -x /sbin/getty -o -x /bin/getty ]; then
+	# busybox
+	GETTY=getty
+elif [ -x /sbin/agetty -o -x /bin/agetty ]; then
+	# util-linux
+	GETTY=agetty
+fi
+
+exec setsid ${GETTY} ${GETTY_ARGS} -nl /usr/bin/ly tty2 "${BAUD_RATE}" "${TERM_NAME}"