'RELENG_3_5_0_RELEASE'.

This commit was manufactured to restore the state of the 3.5-RELEASE image.
Releases prior to 5.3-RELEASE are omitting the secure/ and crypto/ subdirs.

dial-on-demand, packet filtering, idle timeouts, etc).  The IPX support
is pretty much there but more work needs to be done in sys-bsd.c for
the interface ioctls (Linux has a very different way of configuring IPX
interfaces).

Along the way some things have temporarily been lost due to very messy
conflicts.  I will recover them shortly when I can think clearer.
The main one is the local:remote address override in pap-secrets and
chap-secrets.  Some other home-grown features (dns1,dns2) have been
implemented differently.  Microsoft's chap client auth hacks have been
implemented.  There are bound to be more rough edges...  The changes for
connect-max-retries doesn't fit well with the dial-on-demand code.

Use /etc/ppp/ppp.deny instead of /etc/ppp/ppp.disabled

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.

(more work needs to be done here, I'm trying to beat the supscan)