lalr1.cc: use computed state types

This skeleton uses a single stack of state structures, so it is less
likely to benefit from a stack size reduction than yacc.c (which uses
several stacks: state number, value and location).  But it will reduce
the size of the LAC stack.

This skeleton was already using int for state numbers, so, contrary to
yacc.c, this brings nothing for large automata.

Overall, it is still nicer to make the skeletons alike.

* data/skeletons/lalr1.cc (state_type): Here.

data/skeletons/lalr1.cc

@@ -241,8 +241,8 @@ m4_define([b4_shared_declarations],
     ///               Only used for debbuging output.
     void yy_lac_discard_ (const char* event);]])[
 
-    /// State numbers.
-    typedef int state_type;
+    /// Stored state numbers (used for stacks).
+    typedef ]b4_int_type(0, m4_eval(b4_states_number - 1))[ state_type;
 
     /// Generate an error message.
     /// \param yystate   the state where the error occurred.
@@ -803,7 +803,6 @@ m4_if(b4_prefix, [yy], [],
   int
   ]b4_parser_class[::parse ()
   {
-    // State.
     int yyn;
     /// Length of the RHS of the rule being reduced.
     int yylen = 0;
@@ -916,7 +915,7 @@ b4_dollar_popdef])[]dnl
       --yyerrstatus_;
 
     // Shift the lookahead token.
-    yypush_ ("Shifting", yyn, YY_MOVE (yyla));]b4_lac_if([[
+    yypush_ ("Shifting", static_cast<state_type> (yyn), YY_MOVE (yyla));]b4_lac_if([[
     yy_lac_discard_ ("shift");]])[
     goto yynewstate;
 
@@ -1079,7 +1078,7 @@ b4_dollar_popdef])[]dnl
 
       // Shift the error token.]b4_lac_if([[
       yy_lac_discard_ ("error recovery");]])[
-      error_token.state = yyn;
+      error_token.state = static_cast<state_type> (yyn);
       yypush_ ("Shifting", YY_MOVE (error_token));
     }
     goto yynewstate;