Support WASI target

[Ludea]

It would be awesome if you could support some wasm32-wasi targets.
There is no need to js bindings (wasm-bindgen)

[Hywan]

Hi!

To clarify a little bit: WASI is the ABI, JS would be the target host. So depending on what and how you want to use the resulting Wasm module, JS bindings might be useful (in a Web environment for example). What's your usecase?

[Ludea]

I would like to use https://extism.org/. So it's not a js env.
I prefer to use wasm instead of native dynamic lib linking because of the size of the final binary.
Wasm is smaller than a rust lib.