PR bin/7629 complains about how "umount -a" on netbsd doesn't do
the same thing that it does on other OSs, namely attempt to unmount
all mounted filesystems.  looking back in the cvs logs, I see that
netbsd's umount originally use the fstab for -a, then was changed to
use getmntinfo() for -a, then with the 4.4-lite integration was changed
back to using fstab for -a and added -A to use getmntinfo().

is there any actual benefit in having an option to read the fstab at all?
would anyone object if I changed -a to be the same as -A?

-Chuck