Add a few missing #includes.
diff --git a/dlls/wintrust/wintrust_main.c b/dlls/wintrust/wintrust_main.c
index 76912b3..30bb992 100644
--- a/dlls/wintrust/wintrust_main.c
+++ b/dlls/wintrust/wintrust_main.c
@@ -26,6 +26,7 @@
 #include "guiddef.h"
 #include "wintrust.h"
 #include "mscat.h"
+#include "objbase.h"
 
 #include "wine/debug.h"