Since we're interacting with ITS through the system console, one cause
of build failures is the messages the system job prints to the console
at unpredictable times -- for example, periodic timestamps and
notifications of changes to files in system directories. If one of these
gets printed while we're expecting something else, it's hard for the
Expect script to recover.
Avoid this by patching STYO, the system job's character-printing
routine, to return without doing anything if this system is up.
Adjust the pdset routine so it's matching PDSET's output rather than the
system job's to tell when the time has been set.
