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

Allow ELF Tool Chain elfcopy to be installed as objcopy

ELF Tool Chain elfcopy is nearly a drop-in replacement for GNU objcopy,
but does not currently support PE output which is needed for building
x86 UEFI bits.

Add a src.conf knob to allow installing it as objcopy and set it by
default for aarch64 only, where we don't have a native binutils.

Reviewed by: bapt
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2887