[gentoo-releng] Series of patches for x86_64 UEFI support in catalyst

[Ben Kohler <bkohler@gmail.com>]

Hello,

I'm working on adding UEFI support for x86_64/amd64 builds in
catalyst.  This is going to require some changes in catalyst itself
plus a new cdtar.  Some of this is a bit of a gray area, as far as how
much to bundle prebuilt in the cdtar, versus generating @ runtime via
catalyst.

The UEFI-enabled isos will use grub2, we can provide a prebuilt one or
generate it @ runtime (of course depending on sys-boot/grub on the
host).  If we build grub on demand, then the cdtar will basically just
add a couple of new dirs plus a grub-stub.cfg.

This is my current patch which assumes the cdtar will contain a
pregenerated grub image:

https://github.com/benkohler/catalyst/commit/c7e441d47bd9be60bca29a4d53dfbc82d73e7324

Tool for generating the cdtar used above, is here:

https://github.com/benkohler/cdtar-grub2

If anyone is interested in getting involved with or steering these
changes, please let me know.  This catalyst change and cdtar should be
usable with current releng installcd specs, that's where I've been
testing.

You can also reach me @ iamben on Freenode IRC if you have questions/comments.

Thanks!

-Ben