use UTF8-encoded char* strings in UTF8 build instead of wchar_t* if the current locale uses UTF8;

fall back to widechar CRT functions in the locale is not UTF8


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45663 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/stringops.h

@@ -39,6 +39,8 @@ struct WXDLLIMPEXP_BASE wxStringOperationsWchar
         { return i + n; }
     static wxStringImpl::const_iterator AddToIter(const wxStringImpl::const_iterator& i, int n)
         { return i + n; }
+    static const wxChar* AddToIter(const wxChar *i, int n)
+        { return i + n; }
 
     // returns distance of the two iterators in Unicode characters
     static int DiffIters(const wxStringImpl::iterator& i1,