* src/output.c (output_gram): Rely on nritems, not the

0-sentinel.  See below.
Use -1 as separator, not 0.
* src/bison.simple (yyparse): Subtract 1 to the rule numbers.
Rely on -1 as separator in yyrhs, instead of 0.
* tests/calc.at (AT_CHECK_CALC): Now, the parsers no longer issue
twice `Now at end of input', therefore there are two lines less to
expect.

tests/calc.at

@@ -371,7 +371,7 @@ _AT_CHECK_CALC([$1],
 1 - (2 - 3) = 2
 
 2^2^3 = 256
-(2^2)^3 = 64], [488])
+(2^2)^3 = 64], [486])
 
 # Some parse errors.
 _AT_CHECK_CALC_ERROR([$1], [0 0], [10],