See: https://reviews.freebsd.org/D22706
There was a mistake in the previous diff. I'm not sure how that ended up that way, but there were a few mistakes in variable names. This patch will complete what was originally written and tested.
It changes 3 variable names to correctly use $_fib instead of $fib, and to prepend any ipv6 static routes, instead of ipv4 static routes to the the ipv6 route list.
Sorry for the mess.