Remove unused variables, squelch warning about unused parameter.

ir/opt/opt_osr.c

@@ -1275,6 +1275,8 @@ static void lftr(ir_graph *irg, iv_env *env)
  */
 static void clear_and_fix(ir_node *irn, void *env)
 {
+	(void)env;
+
 	set_irn_link(irn, NULL);
 
 	if (is_Proj(irn)) {

ir/opt/tropt.c

@@ -489,8 +489,6 @@ void optimize_class_casts(void)
 	all_irg_walk(NULL, irn_optimize_class_cast, &changed);
 
 	if (changed) {
-		size_t i, n;
-
 		set_trouts_inconsistent();
 	}