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/cstruct/ppx.nix

@@ -0,0 +1,19 @@
+{ lib, buildDunePackage, cstruct, sexplib, ppxlib, stdlib-shims
+, ounit, cppo, ppx_sexp_conv, cstruct-unix, cstruct-sexp
+}:
+
+if lib.versionOlder (cstruct.version or "1") "3"
+then cstruct
+else
+
+buildDunePackage {
+  pname = "ppx_cstruct";
+  inherit (cstruct) version src useDune2 meta;
+
+  minimalOCamlVersion = "4.08";
+
+  propagatedBuildInputs = [ cstruct ppxlib sexplib stdlib-shims ];
+
+  doCheck = true;
+  checkInputs = [ ounit cppo ppx_sexp_conv cstruct-sexp cstruct-unix ];
+}