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/rust/cargo-expand/default.nix

@@ -0,0 +1,30 @@
+{ lib
+, stdenv
+, rustPlatform
+, fetchFromGitHub
+, libiconv
+}:
+
+rustPlatform.buildRustPackage rec {
+  pname = "cargo-expand";
+  version = "1.0.21";
+
+  src = fetchFromGitHub {
+    owner = "dtolnay";
+    repo = pname;
+    rev = version;
+    sha256 = "sha256-hxG7e5JBDv79eA7IQEdU8kpvE0B69Gqc+aPdCoc6Uf4=";
+  };
+
+  cargoSha256 = "sha256-7CMNJb/HGHPP4CIBEYK+2HC/JAce25qGI86NkSvyxos=";
+
+  buildInputs = lib.optional stdenv.isDarwin libiconv;
+
+  meta = with lib; {
+    description =
+      "A utility and Cargo subcommand designed to let people expand macros in their Rust source code";
+    homepage = "https://github.com/dtolnay/cargo-expand";
+    license = with licenses; [ mit asl20 ];
+    maintainers = with maintainers; [ xrelkd ];
+  };
+}