MFC r314840:xen: add support for canceled suspendSubmitted by: Liuyingdong <liuyingdong@huawei.com>Reviewed by: royger
MFC r286999:xen: allow disabling PV disks and nicsSponsored by: Citrix Systems R&D
MFC r256746:Remove redundant redeclaration of gdtset in sys/xen/xen-os.h, to silencea gcc warning.Approved by: re (glebius)