I built the kernel module like so and ran..
ifconfig gif0 create
ifconfig gif0 destroy
.. without error:
```
INET | INET6
no | no
yes | no
no | yes
yes | yes
```
make tinderbox passed (finally) on universe10a.freebsd.org:
```--------------------------------------------------------------
>>> make universe completed on Tue Jan 12 05:46:57 UTC 2016
(started Tue Jan 12 00:48:41 UTC 2016)
--------------------------------------------------------------```