Bump libc from 0.2.155 to 0.2.156 in /src/rust

Bumps [libc](https://github.com/rust-lang/libc) from 0.2.155 to 0.2.156.
- [Release notes](https://github.com/rust-lang/libc/releases)
- [Changelog](https://github.com/rust-lang/libc/blob/0.2.156/CHANGELOG.md)
- [Commits](rust-lang/libc@0.2.155...0.2.156)

---
updated-dependencies:
- dependency-name: libc
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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