Make sure the interface version is always correctly set

diff --git a/sys/xen/interface/xen-compat.h b/sys/xen/interface/xen-compat.h
index d8c55bfc8f631c9888ff459ff80ad7730d9c6e48..c1cc562c0fab1281f4fdd3e810b94d7adefa9832 100644 (file)
--- a/sys/xen/interface/xen-compat.h
+++ b/sys/xen/interface/xen-compat.h
@@ -33,8 +33,11 @@
 /* Xen is built with matching headers and implements the latest interface. */
 #define __XEN_INTERFACE_VERSION__ __XEN_LATEST_INTERFACE_VERSION__
 #elif !defined(__XEN_INTERFACE_VERSION__)
-/* Guests which do not specify a version get the legacy interface. */
-#define __XEN_INTERFACE_VERSION__ 0x00000000
+/*
+ * The interface version is not set if and only if xen/xen-os.h is not
+ * included.
+ */
+#error "Please include xen/xen-os.h"
 #endif
 
 #if __XEN_INTERFACE_VERSION__ > __XEN_LATEST_INTERFACE_VERSION__