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/dune-private-libs/default.nix

@@ -0,0 +1,25 @@
+{ lib, buildDunePackage, dune_3, stdune }:
+
+buildDunePackage rec {
+  pname = "dune-private-libs";
+
+  duneVersion = "3";
+
+  inherit (dune_3) src version;
+
+  minimalOCamlVersion = "4.08";
+
+  dontAddPrefix = true;
+
+  propagatedBuildInputs = [ stdune ];
+
+  preBuild = ''
+    rm -r vendor/csexp
+  '';
+
+  meta = with lib; {
+    description = "Private libraries of Dune";
+    maintainers = [ maintainers.marsam ];
+    license = licenses.mit;
+  };
+}