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/repr/ppx.nix

@@ -0,0 +1,23 @@
+{ lib, buildDunePackage, ppx_deriving, ppxlib, repr, alcotest, hex }:
+
+buildDunePackage {
+  pname = "ppx_repr";
+
+  inherit (repr) src version useDune2;
+
+  propagatedBuildInputs = [
+    ppx_deriving
+    ppxlib
+    repr
+  ];
+
+  doCheck = false; # tests fail with ppxlib >= 0.23.0
+  checkInputs = [
+    alcotest
+    hex
+  ];
+
+  meta = repr.meta // {
+    description = "PPX deriver for type representations";
+  };
+}