libarchive / bsdtar bug

Hi,

I just got bit by this bug in bsdtar:

  https://github.com/libarchive/libarchive/issues/464

Since libarchive 3.1.2 is over 2 years old now and there have not been
any more releases, what is the right way of going about reporting a
fixed bug so that the FreeBSD version gets a patch downstream?

Marcus