[libcxx-commits] [libcxx] [libcxx] changes `__is_allocator` from a struct to a variable or concept (PR #68629)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Gentle ping -- are we still pursuing this? If nobody is actively pursuing this, I'll close this to get rid of stale reviews in the queue (but it can always be reopened to be pursued later).

https://github.com/llvm/llvm-project/pull/68629