Unicode compilation fixes.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@11661 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/treectrl/treectrl.h

@@ -43,7 +43,7 @@ public:
     MyTreeItemData(const wxString& desc) : m_desc(desc) { }
 
     void ShowInfo(wxTreeCtrl *tree);
-    const char *GetDesc() const { return m_desc.c_str(); }
+    const wxChar *GetDesc() const { return m_desc.c_str(); }
 
 private:
     wxString m_desc;