Start using the exported TEB structure from winternl.h where
possible.

diff --git a/dlls/ntdll/virtual.c b/dlls/ntdll/virtual.c
index f82eab3..0520b7d 100644
--- a/dlls/ntdll/virtual.c
+++ b/dlls/ntdll/virtual.c
@@ -40,6 +40,7 @@
 
 #define NONAMELESSUNION
 #define NONAMELESSSTRUCT
+#include "thread.h"
 #include "winternl.h"
 #include "global.h"
 #include "wine/library.h"