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/development/ocaml-modules/opium_kernel/default.nix

@@ -0,0 +1,44 @@
+{ lib
+, buildDunePackage
+, fetchurl
+
+, ppx_fields_conv
+, ppx_sexp_conv
+
+, cohttp-lwt
+, ezjsonm
+, hmap
+, sexplib
+, fieldslib
+}:
+
+buildDunePackage rec {
+  pname = "opium_kernel";
+  version = "0.18.0";
+
+  useDune2 = true;
+
+  minimumOCamlVersion = "4.04.1";
+
+  src = fetchurl {
+    url = "https://github.com/rgrinberg/opium/releases/download/${version}/opium-${version}.tbz";
+    sha256 = "0a2y9gw55psqhqli3a5ps9mfdab8r46fnbj882r2sp366sfcy37q";
+  };
+
+  doCheck = true;
+
+  buildInputs = [
+    ppx_sexp_conv ppx_fields_conv
+  ];
+
+  propagatedBuildInputs = [
+    hmap cohttp-lwt ezjsonm sexplib fieldslib
+  ];
+
+  meta = {
+    description = "Sinatra like web toolkit for OCaml based on cohttp & lwt";
+    homepage = "https://github.com/rgrinberg/opium";
+    license = lib.licenses.mit;
+    maintainers = [ lib.maintainers.pmahoney ];
+  };
+}