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>

nixos/modules/services/monitoring/prometheus/exporters/knot.nix

@@ -0,0 +1,54 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.knot;
+in {
+  port = 9433;
+  extraOpts = {
+    knotLibraryPath = mkOption {
+      type = types.str;
+      default = "${pkgs.knot-dns.out}/lib/libknot.so";
+      defaultText = literalExpression ''"''${pkgs.knot-dns.out}/lib/libknot.so"'';
+      description = ''
+        Path to the library of <package>knot-dns</package>.
+      '';
+    };
+
+    knotSocketPath = mkOption {
+      type = types.str;
+      default = "/run/knot/knot.sock";
+      description = ''
+        Socket path of <citerefentry><refentrytitle>knotd</refentrytitle>
+        <manvolnum>8</manvolnum></citerefentry>.
+      '';
+    };
+
+    knotSocketTimeout = mkOption {
+      type = types.int;
+      default = 2000;
+      description = ''
+        Timeout in seconds.
+      '';
+    };
+  };
+  serviceOpts = {
+    serviceConfig = {
+      ExecStart = ''
+        ${pkgs.prometheus-knot-exporter}/bin/knot_exporter \
+          --web-listen-addr ${cfg.listenAddress} \
+          --web-listen-port ${toString cfg.port} \
+          --knot-library-path ${cfg.knotLibraryPath} \
+          --knot-socket-path ${cfg.knotSocketPath} \
+          --knot-socket-timeout ${toString cfg.knotSocketTimeout} \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+      SupplementaryGroups = [ "knot" ];
+      RestrictAddressFamilies = [
+        # Need AF_UNIX to collect data
+        "AF_UNIX"
+      ];
+    };
+  };
+}