authentication provider for KerberosV
The login_krb5 and login_krb5-or-pwd utilities implement the KerberosV
authentication mechanism (with an optional fallback to standard password
authentication).

The code is based on OpenBSD 5.5-current before the removal of Kerberos
with a few cleanups.

Maintainer: Antoine Jacoutot <ajacoutot@openbsd.org>
