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/networking/mtr-exporter.nix

@@ -0,0 +1,87 @@
+{ config, lib, pkgs, ... }:
+
+let
+  inherit (lib)
+    maintainers types mkEnableOption mkOption mkIf
+    literalExpression escapeShellArg escapeShellArgs;
+  cfg = config.services.mtr-exporter;
+in {
+  options = {
+    services = {
+      mtr-exporter = {
+        enable = mkEnableOption "a Prometheus exporter for MTR";
+
+        target = mkOption {
+          type = types.str;
+          example = "example.org";
+          description = "Target to check using MTR.";
+        };
+
+        interval = mkOption {
+          type = types.int;
+          default = 60;
+          description = "Interval between MTR checks in seconds.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 8080;
+          description = "Listen port for MTR exporter.";
+        };
+
+        address = mkOption {
+          type = types.str;
+          default = "127.0.0.1";
+          description = "Listen address for MTR exporter.";
+        };
+
+        mtrFlags = mkOption {
+          type = with types; listOf str;
+          default = [];
+          example = ["-G1"];
+          description = "Additional flags to pass to MTR.";
+        };
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.mtr-exporter = {
+      script = ''
+        exec ${pkgs.mtr-exporter}/bin/mtr-exporter \
+          -mtr ${pkgs.mtr}/bin/mtr \
+          -schedule '@every ${toString cfg.interval}s' \
+          -bind ${escapeShellArg cfg.address}:${toString cfg.port} \
+          -- \
+          ${escapeShellArgs (cfg.mtrFlags ++ [ cfg.target ])}
+      '';
+      wantedBy = [ "multi-user.target" ];
+      requires = [ "network.target" ];
+      after = [ "network.target" ];
+      serviceConfig = {
+        Restart = "on-failure";
+        # Hardening
+        CapabilityBoundingSet = [ "" ];
+        DynamicUser = true;
+        LockPersonality = true;
+        ProcSubset = "pid";
+        PrivateDevices = true;
+        PrivateUsers = true;
+        PrivateTmp = true;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectSystem = "strict";
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+      };
+    };
+  };
+
+  meta.maintainers = with maintainers; [ jakubgs ];
+}