Firefox 63 vs. sendmsg()

[Jan Kokemüller]

> Can someone help debug https://bugzilla.mozilla.org/show_bug.cgi?id=1475970#c7 ?
> I'm not familar with socket code.

Could it be related to this bug[1]?
There is a demo program in another bug report[2] that still fails for me
(running a recent -current, r334337).

[1]: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=181741
[2]: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=215933