When running grml-live you might run into:

| Executing    shell: GRMLBASE/45-grub-images
| GRMLBASE/45-grub-images FAILED with exit code 1.

This is caused because grub-efi-amd64-bin is installed in GRML_SMALL and
GRML_FULL only but not in the other classes.

One possible fix would be to add the following two lines to
/etc/grml/fai/config/package_config/GRMLBASE:

PACKAGES aptitude AMD64
grub-efi-amd64-bin

Then it would work whenever someone is using GRMLBASE, *but* it would raise an
error if EXIT_ON_MISSING_PACKAGES is enabled and the user builds a Debian/stable
ISO since grub-efi-amd64-bin is available only in >=Debian/wheezy.

Opinions?