As with the autotools builds, use gtk-4 as the name of the .lib file that
is produced from the build.
Actually this is already done with GTK-3.x with the autotools builds,
but this update is not done there as gtk-3.0.lib/gdk-3.0.lib/gailutil-3.0.lib
was used for such a long time that changing it there might have caused
trouble for people there.
Update the project configs to build GDK/GSK as a static lib and include
them into the GTK+ DLL as a monolithic DLL, which is in line with what is
done in the autotools builds, since the code changes needed for Windows
builds for a monolithic build are now in place.
This adds the initial MSVC build items needed to build GSK under Visual Studio,
this is part of it that is required, we need to add items to the property sheets
to generate the code that is generated via glib-mkenums and glib-compile-resources.
This set includes, with the autotools scripts for the complete:
-GSK project files, which is integrated into the gtk+-4.sln.
-The NMake snippets to build the introspection files for GSK.
-The .bat files to call glib-mkenums to generate the enumeration sources.
We now need C99 features from the compiler which are only supported by
Visual Studio 2013 and later, so drop the MSVC 2008~2012 projects, and make
the baseline supported Visual Studio version be 2013. Update the build files
as a result.
