uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/tools/filesystems/zfstools/default.nix

@@ -0,0 +1,40 @@
+{ lib, stdenv, fetchFromGitHub, ruby, zfs }:
+
+stdenv.mkDerivation rec {
+  pname = "zfstools";
+  version = "0.3.6";
+
+  src = fetchFromGitHub {
+    sha256 = "16lvw3xbmxp2pr8nixqn7lf4504zaaxvbbdnjkv4dggwd4lsdjyg";
+    rev = "v${version}";
+    repo = "zfstools";
+    owner = "bdrewery";
+  };
+
+  buildInputs = [ ruby ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp bin/* $out/bin/
+
+    cp -R lib $out/
+
+    for f in $out/bin/*; do
+      substituteInPlace $f --replace "/usr/bin/env ruby" "ruby -I$out/lib"
+    done
+
+    sed -e 's|cmd.*=.*"zfs |cmd = "${zfs}/sbin/zfs |g' -i $out/lib/zfstools/{dataset,snapshot}.rb
+  '';
+
+  meta = with lib; {
+    inherit version;
+    inherit (src.meta) homepage;
+    description = "OpenSolaris-compatible auto-snapshotting script for ZFS";
+    longDescription = ''
+      zfstools is an OpenSolaris-like and compatible auto snapshotting script
+      for ZFS, which also supports auto snapshotting mysql databases.
+    '';
+    license = licenses.bsd2;
+    platforms = platforms.linux;
+  };
+}