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/filedlg.cpp

@@ -391,7 +391,7 @@ int wxFileDialog::ShowModal()
         }
     }
 
-    of.lpstrFilter  = (LPTSTR)filterBuffer.c_str();
+    of.lpstrFilter  = (LPTSTR)filterBuffer.wx_str();
     of.nFilterIndex = m_filterIndex + 1;
 
     //=== Setting defaultFileName >>=========================================