The task would involve compiling three big and complex C++ libraries (that have no equivalent in other languages) to the respective bytecode formats, and my pas

The task would involve compiling three big and complex C++ libraries (that have no equivalent in other languages) to the respective bytecode formats, and my past experiments (from the time before Emscripten was a thing) were not very successful. Maybe that has improved in the meantime, maybe not. Nothing beats clang's wasm output in that regard (e.g. both Emscripten's 'emcc' and Zig's 'zig cc' are drop-in replacements for a GCC-like toolchain which can produce WASM).