add support of HermitOS

[stlankes]

HermitOS is a library operating system. The handling of the socket streams is compatible to unix. However, other parts are not compatible to Unix. Consequently, HermitOS doesn't belong to the unix family.

To support MIO, MIO's unix is revised to support HermitOS. Currently, the implementation based on the unix system poll.

[stlankes]

We have also version, which based on the branch v0.8.x. Are you interested to integrate HermitOS in the version 0.8?

[Thomasdezeeuw]

We're not the biggest fan of dependency. Any chance we can do this with just the libc crate?

[Thomasdezeeuw]

We have also version, which based on the branch v0.8.x. Are you interested to integrate HermitOS in the version 0.8?

We can backport later.

[stlankes]

Yes, I can understand that dependencies are critical. Our OS is written completely in Rust and a classical C library is missing. hermit-abi is also part of std. Do you think that you can support hermit-abi?

By the way, we used a revised version of your examples in our CI.

[Thomasdezeeuw]

Yes, I can understand that dependencies are critical. Our OS is written completely in Rust and a classical C library is missing. hermit-abi is also part of std. Do you think that you can support hermit-abi?

It was pointed out to me that Hermit does support the libc crate, e.g. rust-lang/libc#3348. If that's the case we're not accepting hermit-abi as dependency.

[mkroening]

Yes, I can understand that dependencies are critical. Our OS is written completely in Rust and a classical C library is missing. hermit-abi is also part of std. Do you think that you can support hermit-abi?

It was pointed out to me that Hermit does support the libc crate, e.g. rust-lang/libc#3348. If that's the case we're not accepting hermit-abi as dependency.

The only code in libc for Hermit are the definitions of C integer types: https://github.com/rust-lang/libc/blob/main/src/hermit/mod.rs

[Thomasdezeeuw]

After a bit of discussion we decided to accept the dependency and support of HermitOS as experimental. If you can address the three comments I made earlier we can merge this.

[stlankes]

Great! The last commit should solve the first comment. For the other comments, we will find a solution. I will do it next week.

[Thomasdezeeuw]

Thanks for making the changes, I'm traveling right now so I can't properly review this until next week.

[stlankes]

The changes aren't finished. I will "ping" you, when I solve everything.

[Thomasdezeeuw]

LGTM.

Is this ready to merge?

[stlankes]

I think that the current version is ready to merge