Make sure that no files except unknwn.h include wine/obj_base.h
directly.

diff --git a/include/objbase.h b/include/objbase.h
index 4aa2c45..26435ce 100644
--- a/include/objbase.h
+++ b/include/objbase.h
@@ -21,24 +21,9 @@
 
 #define _OBJBASE_H_
 
-#include "unknwn.h"
-
-/* the following depend only on obj_base.h */
-#include "wine/obj_base.h"
-#include "wine/obj_misc.h"
-#include "wine/obj_channel.h"
-#include "wine/obj_clientserver.h"
-#include "wine/obj_storage.h"
-
-/* the following depend on obj_storage.h */
-#include "wine/obj_marshal.h"
-#include "wine/obj_moniker.h"
-#include "wine/obj_propertystorage.h"
-
-/* the following depend on obj_moniker.h */
-#include "wine/obj_dataobject.h"
-
-#include "wine/obj_dragdrop.h"
+#define __WINE_INCLUDE_OBJIDL
+#include "objidl.h"
+#undef __WINE_INCLUDE_OBJIDL
 
 #ifndef RC_INVOKED
 /* For compatibility only, at least for now */