This reports shellcheck output for *changed* lines. Preexisting problems are
not reported.

Catch up with shellcheck 0.9.0.

To improve shellcheck usage in chroot-script, add a stub file defining ARCH.

This commit is very minimal. In particular it avoids moving/deduplicating code
and/or any style changes.

This breaks compatibility with running on a wheezy host, but bash in
Debian >= jessie is already fixed.

Remove unnecessary use of `eend 0`, which does effectively nothing.
Leftover from git rev c87dc4ae where we moved from grml-etc-core's
lsb-functions functions to a simplified version of them.

Closes: https://github.com/grml/grml-debootstrap/issues/229

It's required for builds with `--vmefi` and `--efi`, since those depend on mkfs.fat.
Closes: https://github.com/grml/grml-debootstrap/issues/225

Enable `set -e` if environment variables `REPORT_TRAP_ERR`
or `FAIL_TRAP_ERR` are set to `yes`.

related to https://github.com/grml/grml-debootstrap/issues/224

By disabling tty when running tune2fs.

https://github.com/grml/grml-debootstrap/issues/219

Closes: https://github.com/grml/grml-debootstrap/issues/169

This commit introduces a new option --vmefi that will change the VM image
to use GPT instead of MBR and adds an ESP partition. Further it will install
grub in EFI mode with secure boot support.

Closes: https://github.com/grml/grml-debootstrap/issues/134

While refreshing base boxes for Vagrant, let's update Grml ISO
from 2022.11-rc1 to stable release 2022.11.