uapi: Use libc for syscall constants

[cd-work]

This patch switches from internally defined system call constants for
the landlock system calls to the ones defined by libc.

Besides removing unnecessary code already provided by the latest libc,
this also adds support for additional architectures like ARM since the
existing constants were limited to x86_64.

[l0kod]

Thanks! Can you please remove the Cargo.lock from the commit?

[cd-work]

Thanks! Can you please remove the Cargo.lock from the commit?

Sure, want me to add it to the .gitignore to match what Rust generates by default for libraries?

[l0kod]

Please just squash the commits.

[l0kod]

Is it the earlier libc version where the Landlock syscalls have been added? It's a pity that the libc crate is using such versioning because we cannot have any guarantee that the used crate will have these flags… This is unfortunate but I still think this commit is worth it.

[cd-work]

The earliest version is actually 0.2.133, I've changed it to make support a tiny bit better even.

It's a pity that the libc crate is using such versioning because we cannot have any guarantee that the used crate will have these flags

I'm not sure what you mean about this. The negotiation for versions should only ever go up, so it shouldn't be possible to pull landlock and end up with a version under 0.2.133 (after my latest change). So I think we can guarantee that the used crate will have these flags?

[l0kod]

Correct, I was thinking about the 0.* exception but it is unrelated.

[l0kod]

You actually pushed rust-lang/libc#2904, thanks!

[l0kod]

If you want to keep your commit signature, please prefix the subject with "uapi: ", otherwise I'll do it myself.

[l0kod]

Thanks!

I removed the Cargo.lock file.