Kerberized telnetd: -a valid option & eight char limit on account names

[Sam Hartman]

Actually, as I recall, MIT's telnetd will call MIT's login.krb5.
There do seem to be several username size limits in that program, all
based on UT_NAMESIZE.

Looking at Solaris, I think that will get set to 8.

I suspect that we don't handle the case where utmpx has a longer name
size than utmp very well.

I'm not sure what the fix is off the top of my head; forcing
UT_NAMESIZE to 32 might just work, but you would need to check and
make sure it didn't create a buffer overflow.