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/os-specific/linux/usbrelay/daemon.nix

@@ -0,0 +1,36 @@
+{ stdenv, usbrelay, python3 }:
+let
+  python = python3.withPackages (ps: with ps; [ usbrelay-py paho-mqtt ]);
+in
+# This is a separate derivation, not just an additional output of
+# usbrelay, because otherwise, we have a cyclic dependency between
+# usbrelay (default.nix) and the python module (python.nix).
+stdenv.mkDerivation rec {
+  pname = "usbrelayd";
+
+  inherit (usbrelay) src version;
+
+  postPatch = ''
+    substituteInPlace 'usbrelayd.service' \
+      --replace '/usr/bin/python3' "${python}/bin/python3" \
+      --replace '/usr/sbin/usbrelayd' "$out/bin/usbrelayd"
+  '';
+
+  buildInputs = [ python ];
+
+  dontBuild = true;
+
+  installPhase = ''
+    runHook preInstall;
+    install -m 644 -D usbrelayd $out/bin/usbrelayd
+    install -m 644 -D usbrelayd.service $out/lib/systemd/system/usbrelayd.service
+    install -m 644 -D 50-usbrelay.rules $out/lib/udev/rules.d/50-usbrelay.rules
+    install -m 644 -D usbrelayd.conf $out/etc/usbrelayd.conf # include this as an example
+    runHook postInstall
+  '';
+
+  meta = {
+    description = "USB Relay MQTT service";
+    inherit (usbrelay.meta) homepage license maintainers platforms;
+  };
+}