meta_monitor_config_match_current() only matches the number of outputs
and if the output connector, vendor, product and serial match.
In the X backend, this means that we can't use it to bypass doing any
work because it won't detect cases where we actually want to update
ourselves like e.g. an output being turned off either by us or by
another X client (e.g. xrandr).
In the native backend, unlike the xrandr backend, we only get called
on real hotplug events and thus should always trigger the common
hotplug code to (possibly) apply a new mode so the check is pointless
anyway.
https://bugzilla.gnome.org/show_bug.cgi?id=738630
Right now this just has all of the files in one directory. We'll
be introducing more structure to this in the future, and build
a proper backend system.
