-/* goto_map, from_state and to_state --record each shift transition
- which accepts a variable (a nonterminal).
-
- from_state[t] is the state number which a transition leads from and
- to_state[t] is the state number it leads to. All the transitions
- that accept a particular variable are grouped together and
- goto_map[i - ntokens] is the index in from_state and to_state of
- the first of them. */