Merge topic 'libuv-macos-posix-poll'

f54ec4e7f9 libuv: macos: use posix poll instead of kqueue
af330faaf1 libuv: darwin: group kqueue-specific definitions together
0db6402687 libuv: process: de-duplicate conditions for using kqueue

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !9392