more changes to make wx compile without implicit wxString->char* conversion (for STL build)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46553 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/datectlg.cpp

@@ -181,7 +181,7 @@ public:
 
         if ( !s.empty() )
         {
-            pDt->ParseFormat(s, m_format);
+            pDt->ParseFormat(s.c_str(), m_format);
             if ( !pDt->IsValid() )
                 return false;
         }