+/* Remove unreachable states, renumber remaining states, update NSTATES, and
+ write to OLD_TO_NEW a mapping of old state numbers to new state numbers such
+ that the old value of NSTATES is written as the new state number for removed
+ states. The size of OLD_TO_NEW must be the old value of NSTATES. */
+void state_remove_unreachable_states (state_number old_to_new[]);
+