grub-git.nix

    grub2 = pkgs.grub2.overrideAttrs (attr: { 
      src = pkgs.fetchgit { 
        url = "https://git.savannah.gnu.org/git/grub.git"; 
        rev = "a791dc0e3501e2932321a257564a3f27a50673bf";
        sha256 = "04ssz35fxnzpd3dr2i1c0x1w2nk06lwpvmgsrhwsw8fms3cx6y7m";
      };
      nativeBuildInputs = attr.nativeBuildInputs ++ [ 
        pkgs.autoconf
        pkgs.automake
      ];
      prePatch = ''
        # postPatch touches configure
        ${pkgs.stdenv.shell} ./autogen.sh
      '';
      # already applied upstream
      patches = [];
    });