[libc-commits] [libc] [libc][NFC] Fix GCC volatile warning (PR #78509)

[Guillaume Chatelet via libc-commits]

gchatelet wrote:

Then a proper fix is probably to use something like google benchmark [`DoNotOptimize`](https://github.com/google/benchmark/blob/3d293cd67a264701378c46e2ae3b6408d533e093/include/benchmark/benchmark.h#L453-L456).

`volatile` is [broken in many ways](https://www.youtube.com/watch?v=KJW_DLaVXIY).

https://github.com/llvm/llvm-project/pull/78509