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/hardware/sane_extra_backends/brscan4.nix

@@ -0,0 +1,112 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.hardware.sane.brscan4;
+
+  netDeviceList = attrValues cfg.netDevices;
+
+  etcFiles = pkgs.callPackage ./brscan4_etc_files.nix { netDevices = netDeviceList; };
+
+  netDeviceOpts = { name, ... }: {
+
+    options = {
+
+      name = mkOption {
+        type = types.str;
+        description = ''
+          The friendly name you give to the network device. If undefined,
+          the name of attribute will be used.
+        '';
+
+        example = "office1";
+      };
+
+      model = mkOption {
+        type = types.str;
+        description = ''
+          The model of the network device.
+        '';
+
+        example = "MFC-7860DW";
+      };
+
+      ip = mkOption {
+        type = with types; nullOr str;
+        default = null;
+        description = ''
+          The ip address of the device. If undefined, you will have to
+          provide a nodename.
+        '';
+
+        example = "192.168.1.2";
+      };
+
+      nodename = mkOption {
+        type = with types; nullOr str;
+        default = null;
+        description = ''
+          The node name of the device. If undefined, you will have to
+          provide an ip.
+        '';
+
+        example = "BRW0080927AFBCE";
+      };
+
+    };
+
+
+    config =
+      { name = mkDefault name;
+      };
+  };
+
+in
+
+{
+  options = {
+
+    hardware.sane.brscan4.enable =
+      mkEnableOption "Brother's brscan4 scan backend" // {
+      description = ''
+        When enabled, will automatically register the "brscan4" sane
+        backend and bring configuration files to their expected location.
+      '';
+    };
+
+    hardware.sane.brscan4.netDevices = mkOption {
+      default = {};
+      example =
+        { office1 = { model = "MFC-7860DW"; ip = "192.168.1.2"; };
+          office2 = { model = "MFC-7860DW"; nodename = "BRW0080927AFBCE"; };
+        };
+      type = with types; attrsOf (submodule netDeviceOpts);
+      description = ''
+        The list of network devices that will be registered against the brscan4
+        sane backend.
+      '';
+    };
+  };
+
+  config = mkIf (config.hardware.sane.enable && cfg.enable) {
+
+    hardware.sane.extraBackends = [
+      pkgs.brscan4
+    ];
+
+    environment.etc."opt/brother/scanner/brscan4" =
+      { source = "${etcFiles}/etc/opt/brother/scanner/brscan4"; };
+
+    assertions = [
+      { assertion = all (x: !(null != x.ip && null != x.nodename)) netDeviceList;
+        message = ''
+          When describing a network device as part of the attribute list
+          `hardware.sane.brscan4.netDevices`, only one of its `ip` or `nodename`
+          attribute should be specified, not both!
+        '';
+      }
+    ];
+
+  };
+}