pf+TSO patch

[Kristof Provost]

Hi,

I've found a little time to look at the pf TSO issue (which made pf
unusable on Xen VMs, like Amazon EC2).

I've posted the patch here:
https://reviews.freebsd.org/D3779

It still needs a bit more testing, but so far it looks good.

I'd be very grateful for any brave souls who want to give this a try.

This work was very kindly sponsored by RootBSD (rootbsd.net).

Regards,
Kristof