Make pyrepl work in Emscripten

[hoodmane]

Proposal:

Ideally we should use this to make a nice web repl with xtermjs.
cc @ambv

Linked PRs

• gh-124621: Emscripten: Add support for async input devices #136822

[StanFromIreland]

Similar (for WASI): #136251 and discourse topic

[hoodmane]

That's also for Emscripten.

[StanFromIreland]

Ok, so this can be closed as a duplicate then?

[hoodmane]

This is a duplicate of #124621 yeah.

[hoodmane]

Thanks @StanFromIreland !

[StanFromIreland]

I re-close with link so it is clearer for people viewing this issue in the future.