Rollup of 7 pull requests

[frewsxcv]

• Successful merges: Introduce HashStable trait and base ICH implementations on it. #40878, Emit proper lifetime start intrinsics for personality slots #40908, Update cargo submodule #40996, Overhaul Bootstrap (x.py) Command-Line-Parsing & Help Output #41011, Handle symlinks in src/bootstrap/clean.rs (mostly) -- resolves #40860. #41026, Move libXtest into libX/tests #41037, macros: fix bug parsing #[derive] invocations #41050
• Failed merges:

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @eddyb (or someone else) soon.

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[frewsxcv]

@bors r+ p=10

[bors]

📌 Commit d282184 has been approved by frewsxcv

[bors]

⌛ Testing commit d282184 with merge eb2123e...

[bors]

💔 Test failed - status-appveyor