/* Ugh, must be same as Hairpin::print. */
Grob *common = spanner->get_bound (LEFT)->common_refpoint (spanner->get_bound (RIGHT), X_AXIS);
/* Ugh, must be same as Hairpin::print. */
Grob *common = spanner->get_bound (LEFT)->common_refpoint (spanner->get_bound (RIGHT), X_AXIS);