[libcxx-commits] [libcxx] [libc++] Gate _BitInt library extensions behind opt-in macro per P3666R4 (PR #203841)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne requested changes to this pull request.

Per my comment in https://discourse.llvm.org/t/implementing-p3666r4-bit-precise-integers-in-libc/91070/11, I'd like to wait for the WG21 discussion to settle before we make any actual change in libc++.

https://github.com/llvm/llvm-project/pull/203841