Add missing member to WINTRUST_DATA struct.

diff --git a/include/wintrust.h b/include/wintrust.h
index f38ce8d..e86179b 100644
--- a/include/wintrust.h
+++ b/include/wintrust.h
@@ -98,6 +98,7 @@
     HANDLE hWVTStateData;
     WCHAR* pwszURLReference;
     DWORD  dwProvFlags;
+    DWORD  dwUIContext;
 } WINTRUST_DATA, *PWINTRUST_DATA;
 
 typedef struct _CRYPT_TRUST_REG_ENTRY