Enable statx on musl-libc

[neuschaefer]

Description

This PR adds the statx syscall on Linux/musl, which is available since musl 1.2.5.

Closes: #3972

This PR is currently blocked by #3791 and #3978.

Sources

• https://musl.libc.org/releases.html
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/stat.h

Checklist

• Relevant tests in libc-test/semver have been updated
• No placeholder or unstable values like *LAST or *MAX are
  included (see #3131)
• Tested locally (cd libc-test && cargo test --target mytarget);
  especially relevant for platforms that may not be checked in CI

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @JohnTitor (or someone else) some time within the next two weeks.

Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (S-waiting-on-review and S-waiting-on-author) stays updated, invoking these commands when appropriate:

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[tgross35]

@rustbot blocked

[bors]

☔ The latest upstream changes (presumably #4042) made this pull request unmergeable. Please resolve the merge conflicts.

[bors]

☔ The latest upstream changes (presumably #4132) made this pull request unmergeable. Please resolve the merge conflicts.