first phase of transition to unified Unicode build:

1. changed c_str() to return wxCStrData (implicitly convertible to wxChar*)
2. added template type-safe wrappers for vararg functions
3. added wxUniChar class representing single Unicode character
4. changed wxString::operator[] and wxString::iterator to return wxUniChar


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@44865 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/menuitem.cpp

@@ -392,7 +392,7 @@ void wxMenuItem::SetText(const wxString& txt)
 #endif  //owner drawn
         {
             flagsOld |= MF_STRING;
-            data = (wxChar*) m_text.c_str();
+            data = (wxChar*) m_text.wx_str();
         }
 
 #ifdef __WXWINCE__