anchor.diff:  
   - poll the message ring buffer for new messages generated by
     rtapi_print_msg() in other components and log them to syslog
  -  (optionally to stderr too). 
  +  (optionally to stderr too).
   
   - in case of userland thread flavors, observe the rtapi_app process
     (see below) and shut down if it goes away.
  
positive.code:        instances (for instance cross-linking of pins and
         ringbuffers). See also the section 'Multiple instances and the
         shmdrv shared memory driver'.
        
  common startup/shutdown::
         some effort has been made to create a common flow of startup
         and shutdown sequence. This work is not complete (see below
  
negative.code: `MSGD_OPTS=<options to rtapi_msgd>`::
           extra startup options can be passed to rtapi_msgd. A useful
           one is `--stderr` which causes rtapi_msgd to write all log
           output to stderr as well:
  
  `RTAPI_APP_OPTS=<options to rtapi_app>`::
  	 extra startup options can be passed to rtapi_app. The only
  