CFT: xl(4) WOL

Hi,

Here is patch that adds support WOL for xl(4). Note, not all xl(4)
controllers support WOL. Some controllers require additional 3-wire
auxiliary remote wakeup connector to draw power. I don't have the
connector so I don't know whether WOL really works or not but I
did not see any regressions.
If you're user of xl(4) please give it try and let me know whether
I introduced regressions.
You can find latest WOL patch at the following URL.
http://people.freebsd.org/~yongari/xl/xl.wol.patch

Thanks.