add missing iterator decls

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@7765 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Lib/std/std_basic_string.i

@@ -8,9 +8,6 @@
 #include <string>
 %}
 
-#ifdef SWIG_EXPORT_ITERATOR_METHODS
-#endif
-
 
 namespace std {
 
@@ -34,6 +31,14 @@ namespace std {
     
     static const size_type npos;
 
+#ifdef SWIG_EXPORT_ITERATOR_METHODS
+  class iterator;
+  class reverse_iterator;
+  class const_iterator;
+  class const_reverse_iterator;
+#endif
+
+
     %traits_swigtype(_CharT);
     %fragment(SWIG_Traits_frag(_CharT));