o mount (and unmount) devfs in the chroot'd filesystem
o handle umounting devfs in case of a keyboard interrupt
o remove MAKEDEV from the fixit floppy so things fit again (mount_devfs was
added in a separate commit)
o explicitly remove mfsroot.gz and loader.conf when building the cd-rom area
as otherwice cp -Rp aborts when a previous run left identical files around
o increase the number of inodes on the drivers floppy; moving drivers from
the kernel there (to shrink it's size) caused things to overflow
o while we're increasing the driver's floppy inode config, separate out all
parameters from the boot floppy
Approved by: re
6ceb41c273