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/tools/ocaml/opam/installer.nix

@@ -0,0 +1,17 @@
+{ lib, unzip, opam, ocamlPackages }:
+
+ocamlPackages.buildDunePackage {
+  pname = "opam-installer";
+
+  useDune2 = true;
+
+  inherit (opam) version src;
+  nativeBuildInputs = [ unzip ];
+
+  configureFlags = [ "--disable-checks" "--prefix=$out" ];
+  buildInputs = with ocamlPackages; [ opam-format cmdliner ];
+
+  meta = opam.meta // {
+    description = "Handle (un)installation from opam install files";
+  };
+}