Add GRUB2 payload to build system

Since a long time GRUB 2 is a viable payload alternative to SeaBIOS and
FILO. So make it easy for coreboot users to use GRUB 2 as a payload by
integrating it into coreboot’s build system, so it can be selected in
Kconfig.

As the last GRUB 2 release 2.00 is too old and has several bugs when
used as a coreboot payload only allow to build GRUB 2 master until a new
GRUB release is done. The downside is, that accidental breakage in
GRUB’s upstream does not affect coreboot users.

Currently the GRUB 2 payload is built with the default modules which
results in an uncompressed size of around 730 kB. Compressed it has a
size of 340 kB, so it should be useable with 512 kB flash ROMs.

Tested with QEMU.

Change-Id: Ie75d5a2cb230390cd5a063d5f6a5d5e3fab6b354
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/4058
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
4 files changed