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/backup/zrepl.nix

@@ -0,0 +1,57 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+let
+  cfg = config.services.zrepl;
+  format = pkgs.formats.yaml { };
+  configFile = format.generate "zrepl.yml" cfg.settings;
+in
+{
+  meta.maintainers = with maintainers; [ cole-h ];
+
+  options = {
+    services.zrepl = {
+      enable = mkEnableOption "zrepl";
+
+      settings = mkOption {
+        default = { };
+        description = ''
+          Configuration for zrepl. See <link
+          xlink:href="https://zrepl.github.io/configuration.html"/>
+          for more information.
+        '';
+        type = types.submodule {
+          freeformType = format.type;
+        };
+      };
+    };
+  };
+
+  ### Implementation ###
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [ pkgs.zrepl ];
+
+    # zrepl looks for its config in this location by default. This
+    # allows the use of e.g. `zrepl signal wakeup <job>` without having
+    # to specify the storepath of the config.
+    environment.etc."zrepl/zrepl.yml".source = configFile;
+
+    systemd.packages = [ pkgs.zrepl ];
+
+    # Note that pkgs.zrepl copies and adapts the upstream systemd unit, and
+    # the fields defined here only override certain fields from that unit.
+    systemd.services.zrepl = {
+      requires = [ "local-fs.target" ];
+      wantedBy = [ "zfs.target" ];
+      after = [ "zfs.target" ];
+
+      path = [ config.boot.zfs.package ];
+      restartTriggers = [ configFile ];
+
+      serviceConfig = {
+        Restart = "on-failure";
+      };
+    };
+  };
+}