Added `wasm32-wasi` support

[martindevans]

It looks like mlua already supports wasm through wasm32-unknown-emscripten, would it be possible to add wasm32-wasi support as well?

[khvzak]

I would love to support wasi, but currently the blocker is exception handling
See notable limitations on the wasi-sdk page
c++ exceptions or setjmp/longjmp is required for Lua VM

[martindevans]

Thanks for the response.

How does wasm32-unknown-emscripten work around the lack of exceptions or setjmp/longjmp?

[khvzak]

How does wasm32-unknown-emscripten work around the lack of exceptions or setjmp/longjmp?

Seems it support native wasm exceptions if enabled, or javascript exceptions otherwise.
See setjmp-longjmp and C++ exceptions support pages

[Bobbyjoness]

I would love to support wasi, but currently the blocker is exception handling See notable limitations on the wasi-sdk page c++ exceptions or setjmp/longjmp is required for Lua VM

That page links to this. Idk if that is a recent change. Either way this should make it possible to target wasi? I tried modifying lua-src myself but honestly I couldn't figure it out.