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/backup/rdiff-backup/default.nix

@@ -0,0 +1,36 @@
+{ lib, python3Packages, librsync }:
+
+let
+  pypkgs = python3Packages;
+
+in
+pypkgs.buildPythonApplication rec {
+  pname = "rdiff-backup";
+  version = "2.0.5";
+
+  src = pypkgs.fetchPypi {
+    inherit pname version;
+    sha256 = "sha256-VNFgOOYgFO2RbHHIMDsH0vphpqaAOMoYn8LTFTSw84s=";
+  };
+
+  # pkg_resources fails to find the version and then falls back to "DEV"
+  postPatch = ''
+    substituteInPlace src/rdiff_backup/Globals.py \
+      --replace 'version = "DEV"' 'version = "${version}"'
+  '';
+
+  buildInputs = [ librsync ];
+
+  nativeBuildInputs = with pypkgs; [ setuptools-scm ];
+
+  # no tests from pypi
+  doCheck = false;
+
+  meta = with lib; {
+    description = "Backup system trying to combine best a mirror and an incremental backup system";
+    homepage = "https://rdiff-backup.net";
+    license = licenses.gpl2Only;
+    maintainers = with maintainers; [ peterhoeg ];
+    platforms = platforms.all;
+  };
+}