[libcxx-commits] [libcxx] [libc++] Avoid -Wzero-as-null-pointer-constant in operator<=> (PR #79465)

[A. Jiang via libcxx-commits]

frederick-vs-ja wrote:

> And I don't like that this wording introduces UB into something that ought to be compile-time checked. Maybe this is LWG issue material. WDYT?

[LWG3142](https://cplusplus.github.io/LWG/issue3142) is touching a similar area. There are also some conditions for UB which are only based on types, perhaps we should change all of such kinds of UB to IFNDR.

https://github.com/llvm/llvm-project/pull/79465