640178a94f
If a client would attach a buffer to a surface, commit, destroy the buffer and then later set the surface as a cursor, there will be no wl_buffer available to be used by the cursor role. Instead of dereferencing the non-existing wl_buffer resource, handle this situation by logging a warning and treating a prematurely destroyd wl_buffer as if no buffer had been attached. https://bugzilla.gnome.org/show_bug.cgi?id=770992