gdkinternal-quartz.h isn't installed but the headers that included
it are, which which would cause the build to fail if an external
project included one of them.
Also changed the includes in gdkinteral-quartz.h to local for
faster loading.
Some applications need to access gdk_quartz_window_get_nsview,
gdk_quartz_window_get_nswindow, and gdk_quartz_event_get_nsevent
so move these from the private gdkquartz-gtk-only.h to a new
header gdkquartz-cocoa-access.h. Don't include this header in
gdkquartz.h so that user code that doesn't need to access these
functins isn't required to compile with Objective C/C++.
Closes https://gitlab.gnome.org/GNOME/gtk/-/issues/1737
The preprocessor directives for proper OS version support are missing
their last digit, rendering the checks defunct.
Improves on https://gitlab.gnome.org/GNOME/gtk/-/issues/3592 but does
not fully fix as other issues have surfaced down the line.
Closes: https://gitlab.gnome.org/GNOME/gtk/issues/1737
Don't export any functions taking or returning MacOS types in
gdkquartz.h, gdkprivate-quartz.h, or any header that either includes.
The GdkQuartz internal functions are moved to a new header
gdkinternal-quartz.h, the functions used by quartz-specific
Gtk files are moved to another new header gdkquartz-gtk-only.h, and
the key and event enums to a new header gdkkeys-quartz.h.
