the debug superdevice when we're compiled without debug, or the normal
superdevice when we're compiled with debug. If this succeeds, print
an informative comment and exit.
make_devices: Create both debug and normal superdevices.
Wait4 zombies.
make_devices: Don't try if the /dev directory is mounted read-only.
Create daemon superdevice /dev/vinum/controld.
Format a couple of multiline comments conformant with style(9).
the wrong module can cause confusion, including loading both versions
(which conflict with each other) and incorrect ioctls, which cause
unintelligible error messages.
Extend 'start' command: if used without any parameters, vinum scans
all disks known to devstat for vinum drives and reads their
configuration.
