We use a compilation symbol in our build to allow the inclusion of
specific headers while building GTK, to avoid the need to include only
the global header.
Each namespace has its own compilation symbol because we used to have
different libraries, and strict symbol visibility between libraries;
now that we have a single library, and we can use private symbols across
namespaces while building GTK, we should have a single compilation
symbol, and simplify the build rules.
Remove all the old 2.x and 3.x version annotations.
GTK+ 4 is a new start, and from the perspective of a
GTK+ 4 developer all these APIs have been around since
the beginning.
The addition of GdkMonitor broke the quartz backend. This patch restores
that support by adding a new class GdkQuartzMonitor, and by modifying
the existing classes GdkQuartzDisplay and GdkQuartzScreen where
necessary.
It should be noted that this patch is essentially a refactor as no new
functionality that will impact the user has been added or removed.
https://bugzilla.gnome.org/show_bug.cgi?id=779184