    # File lib/phusion_passenger/utils/file_system_watcher.rb, line 101
                    def wait_for_change
                            if !@dirs
                                    return false
                            end

                            while true
                                    if changed?
                                            return true
                                    elsif select([@termination_pipe], nil, nil, @poll_interval)
                                            return nil
                                    end
                            end
                    end