[libc-commits] [libc] [libc] Mutex implementation for single-threaded baremetal (PR #145358)

[Daniel Thornburgh via libc-commits]

mysterymath wrote:

> ```
> 7.24.4.2.2
> The atexit function registers the function pointed to by func, to be called without arguments at
> normal program termination.363) It is unspecified whether a call to the atexit function that does
> not happen before the exit function is called will succeed. 
> ```

Whoa, I'm out of date! That's interesting; C11 doesn't have the second sentence, which would ostensibly put it in scope for 7.1.4 (in the draft): `Implementations may share their own internal objects between threads if the objects are not visible to users and are protected against data races.`

Do we have a go-to policy for cases in libc/libc++ where the standard loosens its requirements from version to version?

https://github.com/llvm/llvm-project/pull/145358