1. some more of "#if wxUSE_XXX" here and there

2. Makefile fixes for Cygwin compilation


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@2773 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/treectrl.h

@@ -15,6 +15,7 @@
 // ----------------------------------------------------------------------------
 // headers
 // ----------------------------------------------------------------------------
+
 #ifdef __GNUG__
     #pragma interface "treectrl.h"
 #endif
@@ -23,6 +24,12 @@
 #include "wx/event.h"
 #include "wx/textctrl.h"
 
+#ifdef __GNUWIN32__
+    // Cygwin windows.h defines these identifiers
+    #undef GetFirstChild
+    #undef GetNextSibling
+#endif // Cygwin
+
 // the type for "untyped" data
 typedef long wxDataType;