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>

pkgs/applications/virtualization/xen/packages.nix

@@ -0,0 +1,59 @@
+{ callPackage
+
+}:
+
+# TODO(@oxij) on new Xen version: generalize this to generate [vanilla slim
+# light] for each ./<version>.nix.
+
+rec {
+  xen_4_10-vanilla = callPackage ./4.10.nix {
+    meta = {
+      description = "vanilla";
+      longDescription = ''
+        Vanilla version of Xen. Uses forks of Qemu and Seabios bundled
+        with Xen. This gives vanilla experince, but wastes space and
+        build time: typical NixOS setup that runs lots of VMs will
+        build three different versions of Qemu when using this (two
+        forks and upstream).
+      '';
+    };
+  };
+
+  xen_4_10-slim = xen_4_10-vanilla.override {
+    withInternalQemu = false;
+    withInternalTraditionalQemu = true;
+    withInternalSeabios = false;
+    withSeabios = true;
+
+    meta = {
+      description = "slim";
+      longDescription = ''
+        Slimmed-down version of Xen that reuses nixpkgs packages as
+        much as possible. Different parts may get out of sync, but
+        this builds faster and uses less space than vanilla. Use with
+        `qemu_xen` from nixpkgs.
+      '';
+    };
+  };
+
+  xen_4_10-light = xen_4_10-vanilla.override {
+    withInternalQemu = false;
+    withInternalTraditionalQemu = false;
+    withInternalSeabios = false;
+    withSeabios = true;
+
+    meta = {
+      description = "light";
+      longDescription = ''
+        Slimmed-down version of Xen without `qemu-traditional` (you
+        don't need it if you don't know what it is). Use with
+        `qemu_xen-light` from nixpkgs.
+      '';
+    };
+  };
+
+  xen-vanilla = xen_4_10-vanilla;
+  xen-slim = xen_4_10-slim;
+  xen-light = xen_4_10-light;
+
+}