[libc-commits] [libc] [libc] Suppress GCC loop optimization warning (PR #132458)

[via libc-commits]

lntue wrote:

Look like you need to guard this for gcc only:
```
/home/runner/work/llvm-project/llvm-project/libc/src/__support/big_int.h:796:32: error: unknown warning group '-Waggressive-loop-optimizations', ignored [-Werror,-Wunknown-warning-option]
  796 | #pragma GCC diagnostic ignored "-Waggressive-loop-optimizations"
```

https://github.com/llvm/llvm-project/pull/132458