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/openvpn.nix

@@ -0,0 +1,39 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.openvpn;
+in {
+  port = 9176;
+  extraOpts = {
+    statusPaths = mkOption {
+      type = types.listOf types.str;
+      description = ''
+        Paths to OpenVPN status files. Please configure the OpenVPN option
+        <literal>status</literal> accordingly.
+      '';
+    };
+    telemetryPath = mkOption {
+      type = types.str;
+      default = "/metrics";
+      description = ''
+        Path under which to expose metrics.
+      '';
+    };
+  };
+
+  serviceOpts = {
+    serviceConfig = {
+      PrivateDevices = true;
+      ProtectKernelModules = true;
+      NoNewPrivileges = true;
+      ExecStart = ''
+        ${pkgs.prometheus-openvpn-exporter}/bin/openvpn_exporter \
+          -openvpn.status_paths "${concatStringsSep "," cfg.statusPaths}" \
+          -web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
+          -web.telemetry-path ${cfg.telemetryPath}
+      '';
+    };
+  };
+}