Link to ocamlfind package 'xen-event' for the Eventchn module

The same OCaml code can be used for both userspace and kernelspace.

We keep the C stubs in-tree for now.

We also remove the hack where we advertised a 'xenctrl' package.
Hopefully out-of-tree drivers can depend only on xen-event.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Link to ocamlfind package 'xen-grant' for the Gnt module

The same OCaml code can be used for both userspace and
kernelspace.

We keep the C stubs in-tree for now.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xen: rename event,grant stubs to match userspace

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xen: depend on xen-{event,grant} in the META.in

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xen: map the grant table on demand

Previously we relied on a top-level bindings. In case the top-level
binding evaluation order changes, we map the grant table on first
use instead.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge branch 'disaggregate' of git://github.com/djs55/mirage-platform

Conflicts:
	xen/_vars