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/development/python-modules/rarfile/default.nix

@@ -0,0 +1,42 @@
+{ lib, buildPythonPackage, fetchFromGitHub, pytestCheckHook, nose, libarchive, glibcLocales, isPy27
+# unrar is non-free software
+, useUnrar ? false, unrar
+}:
+
+assert useUnrar -> unrar != null;
+assert !useUnrar -> libarchive != null;
+
+buildPythonPackage rec {
+  pname = "rarfile";
+  version = "4.0";
+  disabled = isPy27;
+
+  src = fetchFromGitHub {
+    owner = "markokr";
+    repo = "rarfile";
+    rev = "v${version}";
+    sha256 = "0gpriqkvcb6bsccvq8b099xjv5fkjs0d7g4636d5jphy417jxk5m";
+  };
+
+  checkInputs = [ pytestCheckHook nose glibcLocales ];
+
+  prePatch = ''
+    substituteInPlace rarfile.py \
+  '' + (if useUnrar then
+        ''--replace 'UNRAR_TOOL = "unrar"' "UNRAR_TOOL = \"${unrar}/bin/unrar\""
+        ''
+       else
+        ''--replace 'ALT_TOOL = "bsdtar"' "ALT_TOOL = \"${libarchive}/bin/bsdtar\""
+        '')
+     + "";
+  # the tests only work with the standard unrar package
+  doCheck = useUnrar;
+  LC_ALL = "en_US.UTF-8";
+  pythonImportsCheck = [ "rarfile" ];
+
+  meta = with lib; {
+    description = "RAR archive reader for Python";
+    homepage = "https://github.com/markokr/rarfile";
+    license = licenses.isc;
+  };
+}