xen: export ioctl headers to userspace

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/include/Kbuild b/include/Kbuild
index d8c3e3c..fe36acc 100644
--- a/include/Kbuild
+++ b/include/Kbuild
@@ -8,3 +8,4 @@
 header-y += rdma/
 header-y += video/
 header-y += drm/
+header-y += xen/
diff --git a/include/xen/Kbuild b/include/xen/Kbuild
new file mode 100644
index 0000000..4e65c16
--- /dev/null
+++ b/include/xen/Kbuild
@@ -0,0 +1 @@
+header-y += evtchn.h