Use #include "foo.h" for including Windows headers in dlls/, use
#include <bar.h> for including Windows headers in include/.

diff --git a/include/xmldom.idl b/include/xmldom.idl
index 47321f7..86dcd1b 100644
--- a/include/xmldom.idl
+++ b/include/xmldom.idl
@@ -16,8 +16,8 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include "xmldomdid.h"
-#include "idispids.h"
+#include <xmldomdid.h>
+#include <idispids.h>
 
 import "ocidl.idl";