Add wasm32-wasip2 target support

[nickrum]

The wasm32-wasip2 target will be a tier 2 target starting with Rust 1.82 and will gain improved socket support in Rust 1.83, so it felt like it made sense to add support for WASIp2 now. If WASIp1 support is a requirement for merging this, I can look into that as well.

Tests are all passing locally. They can be run by having wasmtime installed and setting CARGO_TARGET_WASM32_WASIP2_RUNNER="wasmtime --wasi inherit-network".

Marked as a draft for now since some definitions should be move to rust/libc before merging. I'll do that as soon as I get confirmation on the general direction of this PR.

Closes #268

[nickrum]

The build failure seems to be coming from the fact that std::os::fd was stabilized in Rust 1.66, but the MSRV of this crate is 1.63. In theory, the imports needed are also exported through std::os::wasi, but that module hasn't been stabilized for the wasm32-wasip2 target yet.
Not exactly sure how to move this forward. Is there a chance to increase the MSRV?

[Thomasdezeeuw]

The build failure seems to be coming from the fact that std::os::fd was stabilized in Rust 1.66, but the MSRV of this crate is 1.63. In theory, the imports needed are also exported through std::os::wasi, but that module hasn't been stabilized for the wasm32-wasip2 target yet. Not exactly sure how to move this forward. Is there a chance to increase the MSRV?

That's nice spot Rust put us in... We're not going to increase the MSRV with also doing a version bump, which I don't want to any time soon to be honest.

Maybe we can say the MSRV for wasi p2 is higher? It's not ideal, but I don't see any other solution.

[Darksonn]

Maybe we can say the MSRV for wasi p2 is higher? It's not ideal, but I don't see any other solution.

Seems okay to me.

[Thomasdezeeuw]

@nickrum what is the status of this?

[nickrum]

@Thomasdezeeuw This was blocked by a release of libc containing rust-lang/libc#3981 and should be ready for review now.

CI / Check is currently failing for armv7-sony-vita-newlibeabihf because of rust-lang/rust#132921, which will be fixed by rust-lang/rust#132977.

FreeBSD is currently failing because of #534, which will be fixed by #535.