Simplify use the size method instead of distance

Author: Remi Delmas

src/util/irep_hash_container.cpp

@@ -55,12 +55,7 @@ void irep_hash_container_baset::pack(
   {
     // we pack: the irep id, the sub size, the subs, the named-sub size, and
     // each of the named subs with their ids
-#if NAMED_SUB_IS_FORWARD_LIST
-    const std::size_t named_sub_size =
-      std::distance(named_sub.begin(), named_sub.end());
-#else
     const std::size_t named_sub_size = named_sub.size();
-#endif
     packed.reserve(1 + 1 + sub.size() + 1 + named_sub_size * 2);
 
     packed.push_back(irep_id_hash()(irep.id()));

src/util/lispirep.cpp

@@ -46,12 +46,7 @@ void irep2lisp(const irept &src, lispexprt &dest)
   dest.value.clear();
   dest.type=lispexprt::List;
 
-#if NAMED_SUB_IS_FORWARD_LIST
-  const std::size_t named_sub_size =
-    std::distance(src.get_named_sub().begin(), src.get_named_sub().end());
-#else
   const std::size_t named_sub_size = src.get_named_sub().size();
-#endif
   dest.reserve(2 + 2 * src.get_sub().size() + 2 * named_sub_size);
 
   lispexprt id;