Emscripten allows users to provide their own libraries implemented from JS with the --js-library flag. Emscripten itself also provides custom implementations of several libraries, for example, OpenAL - so that code linking against OpenAL transparently includes a JS implementation on top of WebAudio (libopenal.js).
I want to experiment with changes inside some of these built-in JS libraries. Is there a way to substitute one's own implementation in place of one of the built-in ones like libopenal.js, so that custom JS code is included when linking against OpenAL?