pppd now creates /var/run/ttyXn.if file containing the interface name;
check that a 'login' user is not listed in /etc/ppp/ppp.disabled;
check that a 'login' user's shell is listed in /etc/ppp/ppp.shells;
make sure that passwordless 'login' logins are recorded in wtmp and
utmp.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
