diff --git a/dlls/msxml3/tests/schema.c b/dlls/msxml3/tests/schema.c
index 0fcaf757b29..4637d62f8b2 100644
--- a/dlls/msxml3/tests/schema.c
+++ b/dlls/msxml3/tests/schema.c
@@ -30,6 +30,7 @@
 #undef CLSID_DOMDocument
 #include "msxml2did.h"
 #include "dispex.h"
+#include "cguid.h"
 
 #include "wine/test.h"
 
diff --git a/dlls/rpcrt4/ndr_contexthandle.c b/dlls/rpcrt4/ndr_contexthandle.c
index 848d924e970..36deb41d812 100644
--- a/dlls/rpcrt4/ndr_contexthandle.c
+++ b/dlls/rpcrt4/ndr_contexthandle.c
@@ -22,6 +22,7 @@
 #include "ndr_misc.h"
 #include "rpc_assoc.h"
 #include "rpcndr.h"
+#include "cguid.h"
 
 #include "wine/debug.h"
 #include "wine/list.h"
diff --git a/dlls/setupapi/devinst.c b/dlls/setupapi/devinst.c
index f8a4e93efc5..0840341b7d7 100644
--- a/dlls/setupapi/devinst.c
+++ b/dlls/setupapi/devinst.c
@@ -37,6 +37,7 @@
 #include "winioctl.h"
 #include "rpc.h"
 #include "rpcdce.h"
+#include "cguid.h"
 
 #include "setupapi_private.h"
 
diff --git a/dlls/setupapi/tests/devinst.c b/dlls/setupapi/tests/devinst.c
index a02752d2de3..b887bd8977e 100644
--- a/dlls/setupapi/tests/devinst.c
+++ b/dlls/setupapi/tests/devinst.c
@@ -31,6 +31,7 @@
 #include "devpkey.h"
 #include "setupapi.h"
 #include "cfgmgr32.h"
+#include "cguid.h"
 
 #include "wine/heap.h"
 #include "wine/test.h"
diff --git a/include/guiddef.h b/include/guiddef.h
index ba39dd87b44..cc26e8b3a50 100644
--- a/include/guiddef.h
+++ b/include/guiddef.h
@@ -167,6 +167,4 @@ inline bool operator!=(const GUID& guidOne, const GUID& guidOther)
 }
 #endif
 
-extern const IID GUID_NULL;
-
 #endif /* _GUIDDEF_H_ */