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/programs/xonsh.nix

@@ -0,0 +1,86 @@
+# This module defines global configuration for the xonsh.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.programs.xonsh;
+
+in
+
+{
+
+  options = {
+
+    programs.xonsh = {
+
+      enable = mkOption {
+        default = false;
+        description = ''
+          Whether to configure xonsh as an interactive shell.
+        '';
+        type = types.bool;
+      };
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.xonsh;
+        defaultText = literalExpression "pkgs.xonsh";
+        example = literalExpression "pkgs.xonsh.override { configFile = \"/path/to/xonshrc\"; }";
+        description = ''
+          xonsh package to use.
+        '';
+      };
+
+      config = mkOption {
+        default = "";
+        description = "Control file to customize your shell behavior.";
+        type = types.lines;
+      };
+
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    environment.etc.xonshrc.text = ''
+      # /etc/xonshrc: DO NOT EDIT -- this file has been generated automatically.
+
+
+      if not ''${...}.get('__NIXOS_SET_ENVIRONMENT_DONE'):
+          # The NixOS environment and thereby also $PATH
+          # haven't been fully set up at this point. But
+          # `source-bash` below requires `bash` to be on $PATH,
+          # so add an entry with bash's location:
+          $PATH.add('${pkgs.bash}/bin')
+
+          # Stash xonsh's ls alias, so that we don't get a collision
+          # with Bash's ls alias from environment.shellAliases:
+          _ls_alias = aliases.pop('ls', None)
+
+          # Source the NixOS environment config.
+          source-bash "${config.system.build.setEnvironment}"
+
+          # Restore xonsh's ls alias, overriding that from Bash (if any).
+          if _ls_alias is not None:
+              aliases['ls'] = _ls_alias
+          del _ls_alias
+
+
+      ${cfg.config}
+    '';
+
+    environment.systemPackages = [ cfg.package ];
+
+    environment.shells =
+      [ "/run/current-system/sw/bin/xonsh"
+        "${cfg.package}/bin/xonsh"
+      ];
+
+  };
+
+}
+