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

Increase the size and alignment of the setjmp buffer. This will allow for
possible future CPU extentions with larger registers.

jmp_buf's size and alignment are baked into the ABI of third party libraries
and thus are very hard to change later so it is best to waste a small amount
of space now.

Reviewed by: brooks
Differential Revision: https://reviews.freebsd.org/D3956

Add the start of the arm64 machine headers. This is the subset needed to
start getting userland libraries building.

Reviewed by: imp
Sponsored by: The FreeBSD Foundation