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

Account for <machine/fsr.h> no longer being usable for assembler code.

Add jmpbuf offsets. Remove ucontext offsets.

Catch up to jmpbuf changes. Define offsets used from assmebly language
in another file so that it is easy to see what they are and keep them in
sync with the headers (grafted from the kernel generated assym.s).