> Emscripten is quite mature and compiles even very complex C/C++ code without complaining.
Because it's just Clang with WASM target.
Because it's just Clang with WASM target.
You must not forget that JS does not provide support for many of the things that are required to run a C program (e.g. printing), so emscripten needs to take care of providing alternative implementations for all these things.