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/nix-serve.nix

@@ -0,0 +1,91 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.services.nix-serve;
+in
+{
+  options = {
+    services.nix-serve = {
+      enable = mkEnableOption "nix-serve, the standalone Nix binary cache server";
+
+      port = mkOption {
+        type = types.port;
+        default = 5000;
+        description = ''
+          Port number where nix-serve will listen on.
+        '';
+      };
+
+      bindAddress = mkOption {
+        type = types.str;
+        default = "0.0.0.0";
+        description = ''
+          IP address where nix-serve will bind its listening socket.
+        '';
+      };
+
+      openFirewall = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Open ports in the firewall for nix-serve.";
+      };
+
+      secretKeyFile = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = ''
+          The path to the file used for signing derivation data.
+          Generate with:
+
+          ```
+          nix-store --generate-binary-cache-key key-name secret-key-file public-key-file
+          ```
+
+          For more details see <citerefentry><refentrytitle>nix-store</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+        '';
+      };
+
+      extraParams = mkOption {
+        type = types.separatedString " ";
+        default = "";
+        description = ''
+          Extra command line parameters for nix-serve.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.nix-serve = {
+      description = "nix-serve binary cache server";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      path = [ config.nix.package.out pkgs.bzip2.bin ];
+      environment.NIX_REMOTE = "daemon";
+
+      script = ''
+        ${lib.optionalString (cfg.secretKeyFile != null) ''
+          export NIX_SECRET_KEY_FILE="$CREDENTIALS_DIRECTORY/NIX_SECRET_KEY_FILE"
+        ''}
+        exec ${pkgs.nix-serve}/bin/nix-serve --listen ${cfg.bindAddress}:${toString cfg.port} ${cfg.extraParams}
+      '';
+
+      serviceConfig = {
+        Restart = "always";
+        RestartSec = "5s";
+        User = "nix-serve";
+        Group = "nix-serve";
+        DynamicUser = true;
+        LoadCredential = lib.optionalString (cfg.secretKeyFile != null)
+          "NIX_SECRET_KEY_FILE:${cfg.secretKeyFile}";
+      };
+    };
+
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.port ];
+    };
+  };
+}