fix directorout typemap for const std::string&. Adding warning about the new typemap, which is not thread safe

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@6872 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Examples/test-suite/director_string.i

@@ -0,0 +1,36 @@
+%module(directors="1") director_string;
+%include stl.i
+%include std_vector.i
+%include std_string.i
+
+// Using thread unsafe wrapping
+%warnfilter(470) A;
+
+%{
+#include <vector>
+#include <string>
+%}
+
+%feature("director") A;
+%inline %{
+
+struct A
+{
+  A(const std::string& first)
+    : m_strings(1, first)
+  {}
+  
+  virtual ~A() {}
+  
+  virtual const std::string& get_first() const
+  { return get(0); }
+  
+  virtual const std::string& get(int n) const
+  { return m_strings.at(n); }
+
+  std::vector<std::string> m_strings;
+ };
+ 
+ %}
+
+%template(StringVector) std::vector<std::string>;