Try to make the use of the eoftoken valid. Given that its value

is 0 which was also used as a sentinel in ritem, (i) make sure >= 0
is used instead of > 0 where appropriate, (ii), depend upon nritems
instead of the 0-sentinel.
* src/gram.h, src/gram.c (nritems): New.
Expected to be duplication of nitems, but for the time being...
* src/reader.c (packgram): Assert nritems and nitems are equal.
* src/LR0.c (allocate_itemsets, new_itemsets): Adjust.
* src/closure.c (print_closure, print_fderives): Likewise.
* src/gram.c (ritem_print): Likewise.
* src/print.c (print_core, print_grammar): Likewise.
* src/print_graph.c: Likewise.

src/reader.c

@@ -1764,6 +1764,8 @@ packgram (void)
     }
 
   ritem[itemno] = 0;
+  nritems = itemno;
+  assert (nritems == nitems);
 
   if (trace_flag)
     ritem_print (stderr);