(wait_for_property_change): Avoid unlikely timing error.

(wait_for_property_change): Avoid unlikely timing error.

(x_get_foreign_selection): Pass display to
x_start_queueing_selection_events and x_stop_queueing_selection_events.

(x_reply_selection_request): Call x_start_queueing_selection_events
and x_stop_queueing_selection_events.  Handle X protocol errors.