This fetches GRUB1 sources, applies the {graphical, print function,
save default, and ext3_256byte} patches from debian, and applies a
patch to make it work on x86_64 and port it to Mini-OS. By using
libxc, PV-GRUB can then "kexec" the loaded kernel from inside the
domain itself, hence permitting to avoid the security-concerned
pygrub.
Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>