If an unknow command line argument is passed to the NVDA distribution package, NVDA no longer displays error message dialogs endlessly.
This occurred because command line errors are signalled with exit code 2, but the same exit code was also being used to signal NVDA restarts to the launcher.
Now, restarts are signalled to the launcher using exit code 3.
Authors: Patrick ZAJDA <patrick@zajda.fr>, James Teh <jamie@nvaccess.org>
Fixes #3463.