Work on wlr-foreign-toplevel-management-v1.

Not sure we'll keep this in the end but it gives me boxes to check
for now towards splitting up our Cinnamon process. There are
definitely gaps in support versus the current single-process model
but it allows us to begin to identify them.

Author: mtwebster

src/meson.build

@@ -518,6 +518,8 @@ if have_wayland
     'wayland/meta-wayland-dma-buf.h',
     'wayland/meta-wayland-dnd-surface.c',
     'wayland/meta-wayland-dnd-surface.h',
+    'wayland/meta-wayland-foreign-toplevel.c',
+    'wayland/meta-wayland-foreign-toplevel.h',
     'wayland/meta-wayland-gtk-shell.c',
     'wayland/meta-wayland-gtk-shell.h',
     'wayland/meta-wayland-layer-shell.c',
@@ -810,6 +812,7 @@ if have_wayland
   wayland_protocols = [
     ['cursor-shape-v1', 'private', ],
     ['gtk-shell', 'private', ],
+    ['wlr-foreign-toplevel-management-unstable-v1', 'private', ],
     ['wlr-layer-shell-unstable-v1', 'private', ],
     ['idle-inhibit', 'unstable', 'v1', ],
     ['keyboard-shortcuts-inhibit', 'unstable', 'v1', ],