NixOS/nixpkgs — pull request #1213 by wkennington (2013-11-13 22:49:47+00:00)
Title: Use Git Version of Grub

The current version of grub2 doesn't have the same level of boot support for btrfs / zfs that the git version does. This patch adds the option to use a development version of grub which tracks a similar version to that of archlinux / gentoo.
Additionally, update the grub configuration scripts to handle more complex setups such as full zfs on root.