Compilation fix for wxBase.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@20348 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/datacmn.cpp

@@ -36,6 +36,8 @@
 // Useful buffer, initialized in wxCommonInit
 wxChar *wxBuffer = NULL;
 
+#if wxUSE_GUI
+
 // Windows List
 wxWindowList wxTopLevelWindows;
 
@@ -158,3 +160,4 @@ WXDLLEXPORT_DATA(const wxChar *) wxUserResourceStr = wxT("TEXT");
 const wxSize wxDefaultSize(-1, -1);
 const wxPoint wxDefaultPosition(-1, -1);
 
+#endif // wxUSE_GUI