implements the host support for virtio devices in Linux >= 2.6.25
guests. Network performance shows a huge improvement with
virtio_net, which should be good for the build farm (which uses
Samba/CIFS to mount the file system of the host).
* Kernel headers for 2.6.26-rc5 added to build KVM 69. Also added the
2.6.25 headers, which turned out to be too old for KVM 69.
svn path=/nixpkgs/trunk/; revision=11985
