Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

mdoc: add missing -width argument to Bl -tag.

mdoc: terminate quoted strings.

Reviewed by: brueffer

Fix typos, spelling, formatting and mdoc mistakes found by Nobuyuki while
translating these manual pages. Minor corrections by me.

Submitted by: Nobuyuki Koganemaru <n-kogane@syd.odn.ne.jp>

mdoc: order prologue macros consistently by Dd/Dt/Os

Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.

Reviewed by: ru
Approved by: philip, ed (mentors)

Correct the HISTORY section of these man pages to show when the function,
not the "manual page example" was introduced.

Approved by: ed (mentor, implicit)
MFC after: 1 week

Remove duplicate (but commented out) .Sh HISTORY section heading.
It almost "shadows" the ending .El request of a list, which seems
to have caused mdoc buglets in some gss_*.3 manpages.

MFC after: 3 days

Move the Internet Society copyright message so that it appears in the
formatted page as well as the source.

Add a new extensible GSS-API layer which can support GSS-API plugins,
similar the the Solaris implementation. Repackage the krb5 GSS mechanism
as a plugin library for the new implementation. This also includes a
comprehensive set of manpages for the GSS-API functions with text mostly
taken from the RFC.

Reviewed by: Love Hörnquist Åstrand <lha@it.su.se>, ru (build system), des (openssh parts)