dnsmasq: add ignore hosts dir to dnsmasq init script

When running multiple instances of dnsmasq, for example one being for the lan
and another for a guest network, it might not be desirable to have the same dns names
configured in both networks

Signed-off-by: João Henriques <joaoh88@gmail.com>

package/network/services/dnsmasq/files/dnsmasq.init

@@ -1012,7 +1012,12 @@ dnsmasq_start()
 
 	xappend "--dhcp-broadcast=tag:needs-broadcast"
 
-	xappend "--addn-hosts=$(dirname $HOSTFILE)"
+	config_get_bool ignore_hosts_dir "$cfg" ignore_hosts_dir 0
+	if [ "$ignore_hosts_dir" = "1" ]; then
+		xappend "--addn-hosts=$HOSTFILE"
+	else
+		xappend "--addn-hosts=$(dirname $HOSTFILE)"
+	fi
 
 	config_get dnsmasqconfdir "$cfg" confdir "/tmp/dnsmasq.d"
 	xappend "--conf-dir=$dnsmasqconfdir"