Qt relies on kqueue rather than FSEvents to monitor the directories on MacOSX

Apparently the latest Qt relies on kqueue rather than FSEvents to monitor the directories.

Our Qt application crashes when we monitor more than a couple thousand directories with QFileSystemWatcher on MacOSX.

This is a known limitation of kqueue, and as explained in bug #2478 the solution is to use FSEvents instead:
https://bugreports.qt-project.org/browse/QTBUG-2478

We prepared a small PoC to reproduce the problem, you can find it here:
git clone https://github.com/stolowski/qt-fswatcher-test.git
cd qt-fswatcher-test.git
qmake
make
./qt-fswatcher-test