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

diff --git a/include/strmif.idl b/include/strmif.idl
index c2ef913..fd40f5f 100644
--- a/include/strmif.idl
+++ b/include/strmif.idl
@@ -18,10 +18,10 @@
 
 import "objidl.idl";
 
-#include "devenum.idl"
+#include <devenum.idl>
 
-#include "axcore.idl"
+#include <axcore.idl>
 
-#include "axextend.idl"
+#include <axextend.idl>
 
-#include "dyngraph.idl"
+#include <dyngraph.idl>