The destroyed signal that was emitted if an imported surface was not
available when created, for example if the handle was invalid or
already unexported, was emitted on the wrong resource.
Commit d714a94d9 added support for stable xdg-shell surfaces while
preserving old unstable zxdg-shell v6 ones, but committed a mistake
in checking for both in the xdg_exporter.export error condition
paths. We want to check that the surface is neither of both.
https://gitlab.gnome.org/GNOME/mutter/issues/63Closes: #63
This commits adds support for exporting xdg_surface handles via
xdg_exporter and importing them via xdg_importer.
This bumps the required wayland-protocols version to 1.6.
https://bugzilla.gnome.org/show_bug.cgi?id=769786
