configurePhase = ''
        runHook preConfigure
        ln -sv ${configfile} \${buildRoot:=$(pwd)/../build}/.config
        make $makeFlags "''${makeFlagsArray[@]}" oldconfig
        runHook postConfigure

        make $makeFlags prepare
        actualModDirVersion="$(cat $buildRoot/include/config/kernel.release)"
        if [ "$actualModDirVersion" != "${modDirVersion}" ]; then
          echo "Error: modDirVersion specified in the Nix expression is wrong, it should be: $actualModDirVersion"
          exit 1
        fi

        # Note: we can get rid of this once http://permalink.gmane.org/gmane.linux.kbuild.devel/13800 is merged.
        buildFlagsArray+=("KBUILD_BUILD_TIMESTAMP=$(date -u -d @$SOURCE_DATE_EPOCH)")
      '';
triggers

error: undefined variable ‘pwd’ at /home/teto/nixpkgs/pkgs/os-specific/linux/kernel/manual-config.nix:106:46
(use ‘--show-trace’ to show detailed location information)