python310Packages.json-stream-rs-tokenizer: fix darwin build

pkgs/development/python-modules/json-stream-rs-tokenizer/default.nix

@@ -1,8 +1,10 @@
 { lib
+, stdenv
 , buildPythonPackage
 , fetchFromGitHub
 , rustPlatform
 , cargo
+, darwin
 , rustc
 , setuptools-rust
 , json-stream-rs-tokenizer
@@ -38,6 +40,10 @@ buildPythonPackage rec {
     rustc
   ];
 
+  buildInputs = lib.optionals stdenv.isDarwin [
+    darwin.libiconv
+  ];
+
   # Tests depend on json-stream, which depends on this package.
   # To avoid infinite recursion, we only enable tests when building passthru.tests.
   doCheck = false;