Support for trigonometric functions

[JeromeDesfieux]

From my understanding, WebAssembly does not provide built in functions for trigonometry. And as a consequence, the performance of such functions when porting from C++ (with Emscripten using musl implementation) are very bad. JavaScript is very much better.

That would be extremely nice if such functions can be builtin in WebAssembly. One of application domain of WebAssembly is running 3D/Graphics apps in near native C++ performance which is using a lot of trigonometry.

Please see https://github.com/emscripten-core/emscripten/issues/19284 for more details and measures.