DECC$ALLOW_UNPRIVILEGED_NICE

   With DECC$ALLOW_UNPRIVILEGED_NICE enabled, the nice function
   exhibits its legacy behavior of not checking the privilege of
   the calling process (that is, any user may lower the nice value
   to increase process priorities). Also, when the caller sets a
   priority above MAX_PRIORITY, the nice value is set to the base
   priority.

   With DECC$ALLOW_UNPRIVILEGED_NICE disabled, the nice function
   conforms to the X/Open standard of checking the privilege of the
   calling process (only users with ALTPRI privilege can lower the
   nice value to increase process priorities), and when the caller
   sets a priority above MAX_PRIORITY, the nice value is set to MAX_
   PRIORITY.