the rndvar.h is a hangover from OpenBSD/FreeBSD. Its not strictly
needed.

There are a couple of other known issues (e.g., the crypto framework
gets initialized from the pseudo-device attach function, which means
the crypto framework isnt ready when hardwdare devices are configured
and try to attach).

IF you can wait another 3 or 4 hours, I am planning to fix these, and
(thanks to Quentin Garnier) also commit them a hifn 775x driver which
works well enough for experimental use.