[Libvir] Unified Xen patch (third and hopefully final version)

This is the third version of the unified Xen driver patch[1]. It includes Dan's fixes[2] and a minor fix of my own to fix compiles --without-xen. I've checked this and I'm happy with proposing it for inclusion in libvirt. Rich. [1] https://www.redhat.com/archives/libvir-list/2007-March/thread.html#00409 [2] https://www.redhat.com/archives/libvir-list/2007-April/msg00007.html -- Emerging Technologies, Red Hat http://et.redhat.com/~rjones/ 64 Baker Street, London, W1U 7DF Mobile: +44 7866 314 421 Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Directors: Michael Cunningham (USA), Charlie Peters (USA) and David Owens (Ireland)