PR 210687 was about this. I don't have the skill/time to do this myself. If the port maintaner can do this, I'll be very grateful! Thanks!
Currently, I have no idea how to add parallel support.
Draft patch in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=226912 Closing this as duplicate. *** This bug has been marked as a duplicate of bug 226912 ***
*** This bug has been marked as a duplicate of bug 237751 ***