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

Rework the handling of the children for the pthread_vfork_test. The
trivial handler for SIGCHLD is installed, and SIGCHLD is blocked, to
not abandon our zombies to init(8). This way, the zombies are around
slightly longer, allowing to actually exercise the logic for p_pwait
use by the test.

MFC after: 1 week

This is simple testing program for revision 185647.
It invokes multiple parallel threads and each thread calls vfork()
system call.

Approved by: kib