[PATCH] D53486: [libcxx] Only define __libcpp_is_floating_point<_Float16> for Clang

[Louis Dionne via Phabricator]

ldionne added a comment.

The original intent of the change was to allow `isnan` to be called on `__fp16`. It may be possible to achieve the same goal without adding specializations of `is_floating_point`, which promises more than what we want to promise here (I agree with Marshall).


Repository:
  rCXX libc++

https://reviews.llvm.org/D53486