Forced ASM.JS compilation through C++

This is slightly in connection with my previous post.

AFAIK, ASM.JS/WASM provides a speed boost over JIT compiled JavaScript, so it could be beneficial to modify the native Linux C++ backend to be able to compile for either WASM/ASM.JS or ELF.

This could give a non-negligible speed boost to games running in supported browsers, as it also avoids GC pauses and could open up later multiprocess support when WASM will get a shared memory thread model.

Interested about the possibilities here too.

Kore (C++ core used in Armory) already has an emscripten backend, so that will likely be the easiest way to approach this for a start.