backport of fix for non-unicode builds

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_9_0_BRANCH@60781 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/core/cfstring.cpp

@@ -670,7 +670,7 @@ wxString wxCFStringRef::AsString(wxFontEncoding WXUNUSED_IN_UNICODE(encoding))
     #error "unsupported unicode representation"
   #endif
 #else
-    wxString result(buf, cStrLen) ;
+    result = wxString(buf, cStrLen) ;
 #endif
     
     delete[] buf ;