NAME
        ExternalSync -- provide external source clock for a player's
                        conductor. (V37)

   SYNOPSIS
        result = ExternalSync(player, minTime, maxTime);
        D0                    A0      D0       D1

        bool externalsync(struct player *, long, long);

   FUNCTION
        Allows external applications to constrain conductor time between
        minTime and maxTime, with the restraint that time can never run
        backwards. Does nothing if the given player is not the
        current External Sync source.

   INPUTS
        player - player referencing the conductor to change
        minTime, maxTime - time constraints

   RESULTS
        result - TRUE if everything went OK, FALSE if the player is not the
                 current sync source or there is no conductor for the player.