reported in PR #3668 from maximum entropy <entropy@tanstaafl.bernstein.com>.
The problem: The unit number is not being conveyed to the configuration
crosscheck with root is a network interface; the device number is set
to NODEV, which sets up the (correct) defaults for swap/dump devices.
We can't change NODEV to a unit number, as the PR's patch suggests, as
this breaks the swap/dump defaults. Rewriting that code is not really
justified, since it's soon to be obsoleted.
The kludge: add an "nv_ifunit" member to struct nvlist, which convey's
a network interface's unit number to the crosscheck routine. It's not
pretty, but it's not terribly invasive, and can be garbage-collected
easily when the swap/dump goo is obsoleted.
267e8357fc