public: drop assembly equates from errno.h again

This wasn't a good idea after all - make them unavailable except for
legacy code using an older interface version.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/include/public/errno.h
+++ b/xen/include/public/errno.h
@@ -32,7 +32,7 @@
 #define XEN_ERRNO(name, value) XEN_##name = value,
 enum xen_errno {
 
-#else /* !__ASSEMBLY__ */
+#elif __XEN_INTERFACE_VERSION__ < 0x00040700
 
 #define XEN_ERRNO(name, value) .equ XEN_##name, value
 
--- a/xen/include/public/xen-compat.h
+++ b/xen/include/public/xen-compat.h
@@ -27,7 +27,7 @@
 #ifndef __XEN_PUBLIC_XEN_COMPAT_H__
 #define __XEN_PUBLIC_XEN_COMPAT_H__
 
-#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040600
+#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040700
 
 #if defined(__XEN__) || defined(__XEN_TOOLS__)
 /* Xen is built with matching headers and implements the latest interface. */