aout support almost working now

[walt <wa1ter@myrealbox.com>]

With Bean's last two commits I can almost replace legacy with grub2
at least on x86.  I have still one problem with the aout support that
Bean posted as a patch on Jan 27.

Using legacy, which loads the FreeBSD /boot/loader as the 'kernel',
loader then reads its config files from the /boot directory so it
knows what parameters to pass to the real kernel and also what menu
items to show the user.

Using grub2 with Bean's aout patch,  I can load /boot/loader and
then boot it successfully, but it seems that 'loader' can't find
its config files in the /boot directory.  This is what it prints:

Can't work out which disk we are booting from.
Guessed BIOS device 0xffffffff not found by probes,
defaulting to disk0:  can't load "kernel".

At least on my machine, disk0 is the floppy drive and loader does
actually go to try to read it before printing the error messages
I listed, and then it drops to its interactive prompt.

By examining the loader's variables it's clear that it never found
its usual config files in /boot.

BTW, I did set 'root' and 'prefix' to point at the correct partition
before booting the loader.

Any ideas what else to try?