Since Xen 4.11 is imported into ports, sysutils/xen-tools was renamed to sysutils/xen-tools47 and sysutils/xen-tools11 was added. This causes 'make index' to fail because it cannot find sysutils/xen-tools, which is a dependency of libvirt.
A commit references this bug:
Date: Thu Jul 26 15:44:57 UTC 2018
New revision: 475383
devel/libvirt: fix xen-tools dependency
sysutils/xen-tools was moved to sysutils/xen-tools47, so update
Reported by: Ting-Wei Lan
(In reply to commit-hook from comment #1)
Thanks for reporting that, should be fixed now.