Update aufs source.
aufs3 mmap modify.
Enable devtmpfs & aufs
Merge pull request #2 from sunadm/master

Update aufs file system support.
xpenology: XEN block devices are now seen as system disks.
xpenology: XEN changed block device prefixes.

The XEN block device driver renames the disks so they prefix
with xvd. Devices with xvd names aren't seen by xpenology.
Here we amend it so that unless a xvd device has been specified
in the XEN config, sd will be used instead, thus enabling
compatibility.
xpenology: Boot param for number of XEN PV HDDs.

To resolve a crash where the offset used for internal XEN devices
clashes with non XEN virtualised hard drives. This boot param
can be used to determine which min offset the other internal drives
should use. The crash is due to the way PV drives are handled
using xen block drivers and not the traditonal scsi driver.

i.e xen (sda,sdb) = 2

Ideally this should be automated and not manually set by the user.