build: re-enable compiler warnings, and fix them

There are warnings (-Wextra) in generated C++ code:

  ltlparse.cc: In member function 'ltlyy::parser::symbol_number_type
  ltlyy::parser::by_state::type_get() const':
  ltlparse.cc:452:33: warning: enumeral and non-enumeral type in
  conditional expression
      return state == empty_state ? empty_symbol : yystos_[state];

Reported by Alexandre Duret-Lutz.

It turns out that -Wall and -Wextra were disabled because of a stupid
typo.

* configure.ac: Fix the stupid typo.
* data/lalr1.cc, src/AnnotationList.c, src/InadequacyList.c,
* src/ielr.c, src/print.c, src/scan-code.l, src/symlist.c,
* src/symlist.h, src/symtab.c, src/tables.c, tests/actions.at,
* tests/calc.at, tests/cxx-type.at, tests/glr-regression.at,
* tests/named-refs.at, tests/torture.at:
Fix warnings, mostly issues about variables used only with assertions,
which are disabled with -DNDEBUG.

src/AnnotationList.c

@@ -546,7 +546,7 @@ AnnotationList__compute_from_inadequacies (
                     AnnotationList__insertInto (annotation_node,
                                                 &annotation_lists[s->number],
                                                 s->nitems);
-                  aver (b);
+                  aver (b); (void) b;
                 }
                 /* This aver makes sure the
                    AnnotationList__computeDominantContribution check above

src/InadequacyList.c

@@ -66,7 +66,7 @@ symbol *
 InadequacyList__getContributionToken (InadequacyList const *self,
                                       ContributionIndex i)
 {
-  aver (0 <= i && i < self->contributionCount);
+  aver (0 <= i && i < self->contributionCount); (void) i;
   return self->inadequacy.conflict.token;
 }
 

src/ielr.c

@@ -1102,7 +1102,10 @@ ielr (void)
     else if (STREQ (type, "canonical-lr"))
       lr_type = LR_TYPE__CANONICAL_LR;
     else
-      aver (false);
+      {
+        aver (false);
+        abort ();
+      }
     free (type);
   }
 

src/print.c

@@ -343,6 +343,7 @@ print_reductions (FILE *out, state *s)
             || (STREQ (default_reductions, "consistent")
                 && default_reduction_only)
             || (reds->num == 1 && reds->rules[0]->number == 0));
+      (void) default_reduction_only;
       free (default_reductions);
     }
 }

src/scan-code.l

@@ -664,7 +664,7 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 
     case LHS_REF:
       if (!type_name)
-        type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
+        type_name = symbol_list_n_type_name_get (rule, 0);
 
       if (!type_name)
         {
@@ -695,8 +695,7 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
       if (max_left_semantic_context < 1 - n)
         max_left_semantic_context = 1 - n;
       if (!type_name && 0 < n)
-        type_name =
-          symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
+        type_name = symbol_list_n_type_name_get (effective_rule, n);
       if (!type_name)
         {
           if (union_seen | tag_seen)

src/symlist.c

@@ -190,7 +190,7 @@ symbol_list_n_get (symbol_list *l, int n)
 `--------------------------------------------------------------*/
 
 uniqstr
-symbol_list_n_type_name_get (symbol_list *l, location loc, int n)
+symbol_list_n_type_name_get (symbol_list *l, int n)
 {
   return symbol_list_n_get (l, n)->content.sym->type_name;
 }

src/symlist.h

@@ -124,7 +124,7 @@ symbol_list *symbol_list_n_get (symbol_list *l, int n);
 
 /* Get the data type (alternative in the union) of the value for
    symbol N in rule RULE.  */
-uniqstr symbol_list_n_type_name_get (symbol_list *l, location loc, int n);
+uniqstr symbol_list_n_type_name_get (symbol_list *l, int n);
 
 /* Check whether the node is a border element of a rule. */
 bool symbol_list_null (symbol_list *node);

src/symtab.c

@@ -145,7 +145,7 @@ code_props_type_string (code_props_type kind)
     case printer:
       return "%printer";
     }
-  assert (0);
+  abort ();
 }
 
 /*----------------------------------------.

src/tables.c

@@ -698,7 +698,7 @@ pack_vector (vector_number vector)
 
       if (ok)
         {
-          int loc;
+          int loc PACIFY_CC (= -1);
           int k;
           for (k = 0; k < t; k++)
             {