MFC r332390: make-memstick.sh: put partition args on separate lines

This makes it easier to identify the individual partition types and
facilitates comparisons across architectures.

Sponsored by: The FreeBSD Foundation

MFC r325950, r325953:
r325950:
Sort variables for consistency.

r325953:
Add general configuration files used by release/release.sh for
big-iron installation images.

Sponsored by: The FreeBSD Foundation

MFC r323438: make-memstick.sh: use UFSv2

There's not much practical difference as far as install media is
concerned but newfs creates UFSv2 by default and it is sensible to use
the contemporary UFS version.

I also intend to change makefs to create UFSv2 by default (to match
newfs) so we'll want make-memstick.sh to be explicit, rather than
relying on the host tool's default.

Sponsored by: The FreeBSD Foundation

make-memstick.sh: use 'set -e' to abort if any step fails

Also remove the now-redundant error handling that was only for makefs.

This script was run on an older FreeBSD host that lacked efi-on-mbr
support in makefs. A warning was emitted on the console (from makefs)
but the script continued running and exited with 0.

MFC of r308171 (arm64) and r323178 (other architectures).

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

ARM64: move to GPT scheme in sysinstall

It's time to abandon MBR installations on
ARM64 platforms.

Obtained from: Semihalf
Submitted by: Dominik Ermel <der@semihalf.com>
Sponsored by: Cavium
Reviewed by: gjb, emaste, marcel
Approved by: re (gjb)
Differential Revision: https://reviews.freebsd.org/D6798

Prevent memstick installation medium from attempting to mount
the root filesystem read-write. This causes problems booting
the memstick installation medium from write-protected USB flash
drives.

Submitted by: A.J. Kehoe IV [1], Oliver Jones [2]
PR: 187161 [1], 205886 [2]
MFC after: 1 week
Sponsored by: The FreeBSD Foundation

Do not nest the BSD and MBR partitions, which produces
an unbootable image. Use just an MBR scheme instead.

Sponsored by: The FreeBSD Foundation

Generate the arm64/aarch64 memstick image as MBR instead of
GPT.

Boot tested by: andrew
Sponsored by: The FreeBSD Foundation

Remove the gptboot partition from the arm64 memory stick image,
which is not needed/used.

Sponsored by: The FreeBSD Foundation

Merge the following from ^/projects/release-arm64 to allow
building FreeBSD/arm64 VM images and memstick.img installation
medium:
r281786, r281788, r281792:

r281786:
Add support for building arm64/aarch64 virtual machine images.

r281788:
Copy amd64/make-memstick.sh to arm64/make-memstick.sh for
aarch64 memory stick images.

Although arm64 does not yet have USB support, the memstick
image should be bootable with certain virtualization tools,
such as qemu.

r281792:

Add a buildenv_setup() prototype, intended to be overridden as
needed.

For example, the arm64/aarch64 build needs devel/aarch64-binutils,
so buildenv_setup() in the release.conf for this architecture
handles the installation of the port before buildworld/buildkernel.

Sponsored by: The FreeBSD Foundation

Copy amd64/make-memstick.sh to arm64/make-memstick.sh for
aarch64 memory stick images.

Although arm64 does not yet have USB support, the memstick
image should be bootable with certain virtualization tools,
such as qemu.

Sponsored by: The FreeBSD Foundation