I believe the distributed kernel configuration file with mklivecd is
incorrect, at least when running on -current.  The overlay mounts:

	/rescue/mount_null /ramfs/xxx /xxx

don't work because 'file-system NULLFS' isn't included in the config
file.  I'm not sure if this is a problem for -current only.

		--Steve Bellovin, http://www.cs.columbia.edu/~smb