[libcxx-commits] [libcxx] [libc++] Implement `std::function_ref` (PR #186692)

[Louis Dionne via libcxx-commits]

ldionne wrote:

@huixie90 I added the LLVM 24 release notes and we branched for LLVM 23 now, so I think this can be rebased and merged.

https://github.com/llvm/llvm-project/pull/186692