[clang] Support `guarded_by` attribute and related attributes inside C structs and support late parsing them (PR #95455)

[Aaron Puchert via cfe-commits]

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@@ -764,12 +764,6 @@ doesn't know that munl.mu == mutex.  The SCOPED_CAPABILITY attribute handles
 aliasing for MutexLocker, but does so only for that particular pattern.
 
 
-ACQUIRED_BEFORE(...) and ACQUIRED_AFTER(...) are currently unimplemented.
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-To be fixed in a future update.
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-
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aaronpuchert wrote:

They are implemented, but still under `-Wthread-safety-beta` as far as I know, because there are some weaknesses. If you want to touch this here, I would suggest to write instead that support is still experimental.

https://github.com/llvm/llvm-project/pull/95455