from netbsd;

from netbsd;
Instead of using '#ifdef atari' to handle the differences of Gemdosfs and
Msdosfs, use a flag that can be set by mount_msdos. This is definitely
more flexible.
Fix error in previous change: don't use the local FS mount data before
it's actually allocated. Pass mount arguments to msdosfs_mountfs instead,
and use them (as in iso_mountfs for example).