The kqueue file monitoring backend was misusing G_GNUC_INTERNAL for want
of 'static' in a couple of places and also using it to declare a lock
that was never used at all.
Fix those up.
MacOS provides the O_EVTONLY flag to open(2) which allow to open a file
for monitoring without preventing an unmount of the volume that contains
it.
https://bugzilla.gnome.org/show_bug.cgi?id=688518
Written by Dmitry Matveev as part of GSoC 2011:
http://netbsd-soc.sourceforge.net/projects/kqueue4gio/
This brings native file monitoring support on systems supporting kqueue(3)
(all BSDs) and remove the need to rely on the unmaintained gamin software.
The backend adds GKqueueDirectoryMonitor and GKqueueFileMonitor.
Some parts rewritten by myself (to prevent needing a configuration file).
Helpful inputs from Colin Walters and Simon McVittie.
https://bugzilla.gnome.org/show_bug.cgi?id=679793
