[libcxx-commits] [libcxx] [libc++] Consistently use version guards outside namespace macros (PR #181136)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne approved this pull request.

I think this makes sense. I also used Claude to do a consistency check and it found a couple of missed places:

  These files have the old pattern (namespace opened outside the #if guard) and were not included in the commit:

  | File | Guard |
  |---|---|
  | `__algorithm/clamp.h` | `>= 17` |
  | `__numeric/reduce.h` | `>= 17` |
  | `__numeric/transform_reduce.h` | `>= 17` |
  | `__type_traits/is_implicit_lifetime.h` | `>= 23` |
  | `__type_traits/is_within_lifetime.h` | `>= 26` |
  | `__type_traits/reference_converts_from_temporary.h` | `>= 23` |
  | `__utility/as_const.h` | `>= 17` |

https://github.com/llvm/llvm-project/pull/181136