
If a command is passed to `start_child` which is NULL, such as in the case when there is no `status_command` specified in the bar config, do not start a child process to listen on stdin. fixes #1140
If a command is passed to `start_child` which is NULL, such as in the case when there is no `status_command` specified in the bar config, do not start a child process to listen on stdin. fixes #1140