Import Xen3 public headers from xen-3.0-testing as of 7 Jan 2006.
Import xenbus sources, from linux sparse tree in the 20060107 xen-3.0
snapshot.
Import non-DPLd Xen public headers from Xen 3.0.2-2
Import Xen 3.1.0 public headers
Import Xen 3.3.0 public headers
re-import xen3-public to rename this to xen-public
Welcome to Xen 4.1.2 headers.

New interfaces for PV drivers:
- Xen transcedent memory
- USB IO
- SCSI IO

PCI IO improvements:
- PCI MSI support
- PCI Express AER support

New features:
- xen honors flags to be placed into guest kernel available pte bits
  if enabled (for grant table)
- support for 128 vcpus
  (old interface is still present and supports up to 32 vcpus)
- PCI passthrough: new hypercalls to support SR-IOV
- new hypercall for physical cpu hotplugging
- new hypercall for physical page offlining
- fixes to compile with clang
- machine check recovery mechanism