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/misc/calibre-server.nix

@@ -0,0 +1,86 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.calibre-server;
+
+in
+
+{
+  imports = [
+    (mkChangedOptionModule [ "services" "calibre-server" "libraryDir" ] [ "services" "calibre-server" "libraries" ]
+      (config:
+        let libraryDir = getAttrFromPath [ "services" "calibre-server" "libraryDir" ] config;
+        in [ libraryDir ]
+      )
+    )
+  ];
+
+  ###### interface
+
+  options = {
+    services.calibre-server = {
+
+      enable = mkEnableOption "calibre-server";
+
+      libraries = mkOption {
+        description = ''
+          The directories of the libraries to serve. They must be readable for the user under which the server runs.
+        '';
+        type = types.listOf types.path;
+      };
+
+      user = mkOption {
+        description = "The user under which calibre-server runs.";
+        type = types.str;
+        default = "calibre-server";
+      };
+
+      group = mkOption {
+        description = "The group under which calibre-server runs.";
+        type = types.str;
+        default = "calibre-server";
+      };
+
+    };
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    systemd.services.calibre-server = {
+        description = "Calibre Server";
+        after = [ "network.target" ];
+        wantedBy = [ "multi-user.target" ];
+        serviceConfig = {
+          User = cfg.user;
+          Restart = "always";
+          ExecStart = "${pkgs.calibre}/bin/calibre-server ${lib.concatStringsSep " " cfg.libraries}";
+        };
+
+      };
+
+    environment.systemPackages = [ pkgs.calibre ];
+
+    users.users = optionalAttrs (cfg.user == "calibre-server") {
+      calibre-server = {
+        home = "/var/lib/calibre-server";
+        createHome = true;
+        uid = config.ids.uids.calibre-server;
+        group = cfg.group;
+      };
+    };
+
+    users.groups = optionalAttrs (cfg.group == "calibre-server") {
+      calibre-server = {
+        gid = config.ids.gids.calibre-server;
+      };
+    };
+
+  };
+
+}