priv allows authorised users to execute commands that run as different
users.

When priv is invoked, it reads a list of authorised commands from a
database file called

	${PREFIX}/etc/priv/<username>

Each line of the database file is a colon-seperated list of fields. 
The first two fields must be specified.  Blank lines or lines
beginning with a ``#'' character are ignored.  The fields, in order,
are:

	expiry date
	user name to run command as
	flags
	command name

The format of the expiry date is YYYYMMDDhhmm.  A date of ``0'' is
interpreted as no expiry date.