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/virtualisation/virtualbox-guest.nix

@@ -0,0 +1,93 @@
+# Module for VirtualBox guests.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.virtualisation.virtualbox.guest;
+  kernel = config.boot.kernelPackages;
+
+in
+
+{
+
+  ###### interface
+
+  options.virtualisation.virtualbox.guest = {
+    enable = mkOption {
+      default = false;
+      type = types.bool;
+      description = "Whether to enable the VirtualBox service and other guest additions.";
+    };
+
+    x11 = mkOption {
+      default = true;
+      type = types.bool;
+      description = "Whether to enable x11 graphics";
+    };
+  };
+
+  ###### implementation
+
+  config = mkIf cfg.enable (mkMerge [{
+    assertions = [{
+      assertion = pkgs.stdenv.hostPlatform.isx86;
+      message = "Virtualbox not currently supported on ${pkgs.stdenv.hostPlatform.system}";
+    }];
+
+    environment.systemPackages = [ kernel.virtualboxGuestAdditions ];
+
+    boot.extraModulePackages = [ kernel.virtualboxGuestAdditions ];
+
+    boot.supportedFilesystems = [ "vboxsf" ];
+    boot.initrd.supportedFilesystems = [ "vboxsf" ];
+
+    users.groups.vboxsf.gid = config.ids.gids.vboxsf;
+
+    systemd.services.virtualbox =
+      { description = "VirtualBox Guest Services";
+
+        wantedBy = [ "multi-user.target" ];
+        requires = [ "dev-vboxguest.device" ];
+        after = [ "dev-vboxguest.device" ];
+
+        unitConfig.ConditionVirtualization = "oracle";
+
+        serviceConfig.ExecStart = "@${kernel.virtualboxGuestAdditions}/bin/VBoxService VBoxService --foreground";
+      };
+
+    services.udev.extraRules =
+      ''
+        # /dev/vboxuser is necessary for VBoxClient to work.  Maybe we
+        # should restrict this to logged-in users.
+        KERNEL=="vboxuser",  OWNER="root", GROUP="root", MODE="0666"
+
+        # Allow systemd dependencies on vboxguest.
+        SUBSYSTEM=="misc", KERNEL=="vboxguest", TAG+="systemd"
+      '';
+  } (mkIf cfg.x11 {
+    services.xserver.videoDrivers = [ "vmware" "virtualbox" "modesetting" ];
+
+    services.xserver.config =
+      ''
+        Section "InputDevice"
+          Identifier "VBoxMouse"
+          Driver "vboxmouse"
+        EndSection
+      '';
+
+    services.xserver.serverLayoutSection =
+      ''
+        InputDevice "VBoxMouse"
+      '';
+
+    services.xserver.displayManager.sessionCommands =
+      ''
+        PATH=${makeBinPath [ pkgs.gnugrep pkgs.which pkgs.xorg.xorgserver.out ]}:$PATH \
+          ${kernel.virtualboxGuestAdditions}/bin/VBoxClient-all
+      '';
+  })]);
+
+}