Commit 896516e54a added a new NFS mount option
used for Kerberized NFSv4.1/4.2 mounts. It specifies that
AUTH_SYS be used for state maintenance (also called system)
operations. This allows the mount to be done without the
"gssname" option or a valid Kerberos TGT being held by the
user doing the mount (so it can be specified in fstab(5) for
example).
Reviewed by: gbe (manpages), karels
MFC after: 3 months
Differential Revision: https://reviews.freebsd.org/D39469
61330e494f