Joel Nises

It seems I'm running into this bug https://github.com/rust-lang/rustup/issues/3036 Nested cargo invocations have issues in recent versions of rustup on windows. I'm trying to run code like: ```rust rustdoc_json::build(BuildOptions::default().toolchain("+nightly")) ``` I'm...

Oh man. c++/rust ffi is not easy 😓 I did the stateful error callback in the end. Seemed like the cleanest interface. Is this an ok way to do it?