Looks like it's finally time to migrate to sys-fs/eudev. udev 197 was unmasked today on amd64, and I would rather not go down that path.
At least I have an alternative, so I don't have to go it alone.
I ended up having to use kmod, instead of module-init-tools. modprobe -l no longer works. I guess that feature is deprecated, and I'm supposed to use find in /lib/modules now. That seems less convenient. Other than that they seem the same.