advpack: Define S_ASYNCHRONOUS in advpub.h.
diff --git a/include/advpub.h b/include/advpub.h
index 442e8e2..6b38ffe 100644
--- a/include/advpub.h
+++ b/include/advpub.h
@@ -25,6 +25,10 @@
 extern "C" {
 #endif
 
+#ifndef S_ASYNCHRONOUS
+#define S_ASYNCHRONOUS  _HRESULT_TYPEDEF_(0x401E8L)
+#endif
+
 typedef struct _CabInfoA
 {
     LPSTR  pszCab;