include: import Xen public headers to hw/xen/interface

There's already a partial set here; update them and pull in a more
complete set.

To start with, define __XEN_TOOLS__ in hw/xen/xen.h to ensure that any
internal definitions needed by Xen toolstack libraries are present
regardless of the order in which the headers are included. A reckoning
will come later, once we make the PV backends work in emulation and
untangle the headers for Xen-native vs. generic parts.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
[dwmw2: Update to Xen public headers from 4.16.2 release, add some in io/,
        define __XEN_TOOLS__ in hw/xen/xen.h, move to hw/xen/interface/]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

include/hw/xen/interface/io/blkif.h

@@ -118,7 +118,7 @@
  *
  *      The underlying storage is not affected by the direct IO memory
  *      lifetime bug.  See:
- *        http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html
+ *        https://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html
  *
  *      Therefore this option gives the backend permission to use
  *      O_DIRECT, notwithstanding that bug.
@@ -341,7 +341,7 @@
  *      access (even when it should be read-only). If the frontend hits the
  *      maximum number of allowed persistently mapped grants, it can fallback
  *      to non persistent mode. This will cause a performance degradation,
- *      since the backend driver will still try to map those grants
+ *      since the the backend driver will still try to map those grants
  *      persistently. Since the persistent grants protocol is compatible with
  *      the previous protocol, a frontend driver can choose to work in
  *      persistent mode even when the backend doesn't support it.
@@ -710,3 +710,13 @@ DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
 #define VDISK_READONLY     0x4
 
 #endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */