This is the sort of info I was trolling for, but what are those platforms and os? Targets llvm doesn't handle yeah c++ makes sense, or c. A sibling mentions xcode, which makes sense. Graphics seems questionable, vulkan support is fine. Windows support has seemed finetoo, the same gui has worked as what we wrote for Linux.

Dependencies. There are billions of lines of C++ out there that have been optimized and production hardened over decades that you might want to reuse. Rust lang interoperability with anything but C sucks in practice.