This should have been part of r74406 but I only rebaked wxWidgets make/project
files themselves and not the samples/utils/demos files in it.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74407 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Merges everything from the branch with only some minor changes, mostly renamed
wxUSE_FSWATCHER_{INOTIFY,KQUEUE} to wxHAS_{INOTIFY,KQUEUE}.
Add wxFileSystemWatcher and related classes.
Also introduces wxEventLoopSource.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62474 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775