Zig 0.11.x support

[notramo]

@frmdstryr, this project doesn't compile on Zig 0.11 preview. Could you add support for it on a separate branch?

[karlseguin]

I've created a fork to work in this. It is working with today's 0.11-dev build, but I'm not sure it's worth merging into master, since 0.11 is still super unstable, but if you want to create a branch for it, I can send a PR to that branch.

It does work with the built-in modules, but since 0.11 currently doesn't support async, my fork only works in single-threaded mode (fine for development, but not much else).