From: "Jason R Thorpe" <thorpej@zembu.com>:
>
> I just whipped up a patch that should allow this in -current, but
> it's tedious to use without some other changes... but, here it is:
>

Cool!  I had already setup some code to copy into ifp->if_sadl, but
I didn't know how to "activate" it.  I'll add the call to if_init()
and see what happens.  Your patch will also let me support setting
the MAC on my 'cec' interface and propagating it down to the link
interfaces.
Hopefully I can get something working tonight, otherwise I should
be able to work on it tomorrow night for sure.

-Andrew