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

Remove argc/argv (-Wunused)

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

NO_MAN= has been deprecated in favor of MAN= for some time, go ahead
and finish the job. ncurses is now the only Makefile in the tree that
uses it since it wasn't a simple mechanical change, and will be
addressed in a future commit.

Style: NO_MAN doesn't need any value.

Use WARNS?= instead of WARNS= in Makefiles so that global warning
settings can override local ones.

Pointed out by: ru

Start the dreaded NOFOO -> NO_FOO conversion.

OK'ed by: core

Add a small regression test that opens a TCP socket, listens on it,
performs a non-blocking connect from another socket, and then closes
the listen socket rather than accepting. This is intended to
exercise the close path in which connections are aborted due to a
close on the listen socket while the connection is in the listen
queue.