Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

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

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

Mark signum unused in signal_handler; bump WARNS to 6

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

Use '%zd' printf format for ssize_t.

Check the return value of shutdown().

Add sigpipe, a simple UNIX domain socket and TCP regression test that is
intended to verify that SIGPIPE is delivered to a process writing or
sending on a socket that has been shut down for write. If available,
SO_NOSIGPIPE is also tested.

This regression test is currently passed by RELENG_4, but not by HEAD or
RELENG_5, due to a bug in the write() code for sockets. SO_NOSIGPIPE is not
present in RELENG_4, however, so is not tested there.

Reported by: Mikko Tyolajarvi <mbsd at pacbell dot net>
PR: 78478