https://github.com/X547/BlackBox-Haiku

Haiku Blackbox version is different from others in 2 points:

It have limited multithreading support because using multiple threads is obligatory for GUI API. But it have one global mutex for all safe Component Pascal code.

It directly interacts with C++ ABI (https://itanium-cxx-abi.github.io/cxx-abi/abi.html), use mangled names, define vtables and C++ RTTI information (it will be nice to integrate it to compiler like COM, but currently don't).