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/servers/monitoring/prometheus/knot-exporter.nix

@@ -0,0 +1,39 @@
+{ stdenv, fetchFromGitHub, lib, python3, nixosTests }:
+
+stdenv.mkDerivation rec {
+  pname = "knot-exporter";
+  version = "unstable-2021-08-21";
+
+  src = fetchFromGitHub {
+    owner = "ghedo";
+    repo = "knot_exporter";
+    rev = "b18eb7db735b50280f0815497475f4c7092a6550";
+    sha256 = "sha256-FGzkO/KHDhkM3PA2urNQcrMi3MHADkd0YwAvu1jvfrU=";
+  };
+
+  dontBuild = true;
+
+  nativeBuildInputs = [ python3.pkgs.wrapPython ];
+  buildInputs = [ python3 ];
+
+  installPhase = ''
+    runHook preInstall
+
+    install -Dm0755 knot_exporter $out/bin/knot_exporter
+    patchShebangs $out/bin
+    buildPythonPath ${python3.pkgs.prometheus-client}
+    patchPythonScript $out/bin/knot_exporter
+
+    runHook postInstall
+  '';
+
+  passthru.tests = { inherit (nixosTests.prometheus-exporters) knot; };
+
+  meta = with lib; {
+    homepage = "https://github.com/ghedo/knot_exporter";
+    description = " Prometheus exporter for Knot DNS";
+    license = licenses.gpl3Only;
+    maintainers = with maintainers; [ ma27 ];
+    platforms = platforms.linux;
+  };
+}