[libcxx-commits] [libcxx] [libc++] Don't use `copy_file_impl_fstream` when not declared (PR #214706)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne commented:

I find the `#elif defined(_LIBCPP_FILESYSTEM_USE_FSTREAM) && defined(_LIBCPP_FILESYSTEM_NEED_FSTREAM)` conditional a bit odd, but I think that's because of the name `_LIBCPP_FILESYSTEM_NEED_FSTREAM`.

I made some suggestions on the PR, let me know what you think about them. I can live with either way but I think the larger refactoring I suggest leaves us with something a bit clearer.

https://github.com/llvm/llvm-project/pull/214706