In principle it would be possible to make a rumpuser-xen-based stub
xenstored, but all the necessary pieces do not yet exist.
So provide a facility to disable compilation of xenstored, and use it
to disable it on rump kernels.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>