Fails to build on wasm32-wasip2

[Ralf Jung]

Trying to build this crate with --target wasm32-wasip2 leads to errors:

error[E0658]: use of unstable library feature 'wasip2'
  --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/maybe_polyfill/std/mod.rs:30:13
   |
30 |             AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd,
   |             ^^^^
   |
   = help: add `#![feature(wasip2)]` to the crate attributes to enable
   = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
  --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/maybe_polyfill/std/mod.rs:30:28
   |
30 |             AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd,
   |                            ^^^^^^^^^^
   |
   = help: add `#![feature(wasip2)]` to the crate attributes to enable
   = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
  --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/maybe_polyfill/std/mod.rs:30:62
   |
30 |             AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd,
   |                                                              ^^^^^^^
   |
   = help: add `#![feature(wasip2)]` to the crate attributes to enable
   = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
   --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/fs/mod.rs:143:29
    |
143 | pub use std::os::wasi::fs::{DirEntryExt, FileExt, FileTypeExt, MetadataExt, OpenOptionsExt};
    |                             ^^^^^^^^^^^
    |
    = help: add `#![feature(wasip2)]` to the crate attributes to enable
    = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
   --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/fs/mod.rs:143:42
    |
143 | pub use std::os::wasi::fs::{DirEntryExt, FileExt, FileTypeExt, MetadataExt, OpenOptionsExt};
    |                                          ^^^^^^^
    |
    = help: add `#![feature(wasip2)]` to the crate attributes to enable
    = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
   --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/fs/mod.rs:143:51
    |
143 | pub use std::os::wasi::fs::{DirEntryExt, FileExt, FileTypeExt, MetadataExt, OpenOptionsExt};
    |                                                   ^^^^^^^^^^^
    |
    = help: add `#![feature(wasip2)]` to the crate attributes to enable
    = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
   --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/fs/mod.rs:143:64
    |
143 | pub use std::os::wasi::fs::{DirEntryExt, FileExt, FileTypeExt, MetadataExt, OpenOptionsExt};
    |                                                                ^^^^^^^^^^^
    |
    = help: add `#![feature(wasip2)]` to the crate attributes to enable
    = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
   --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/fs/mod.rs:143:77
    |
143 | pub use std::os::wasi::fs::{DirEntryExt, FileExt, FileTypeExt, MetadataExt, OpenOptionsExt};
    |                                                                             ^^^^^^^^^^^^^^
    |
    = help: add `#![feature(wasip2)]` to the crate attributes to enable
    = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
  --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/path/arg.rs:26:26
   |
26 | use std::os::wasi::ffi::{OsStrExt, OsStringExt};
   |                          ^^^^^^^^
   |
   = help: add `#![feature(wasip2)]` to the crate attributes to enable
   = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature 'wasip2'
  --> /home/r/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustix-0.38.34/src/path/arg.rs:26:36
   |
26 | use std::os::wasi::ffi::{OsStrExt, OsStringExt};
   |                                    ^^^^^^^^^^^
   |
   = help: add `#![feature(wasip2)]` to the crate attributes to enable
   = note: this compiler was built on 2024-05-19; consider upgrading it if it is out of date