undefined reference to `kevent at FBSD_1.5'

[Otacílio]

After a recent partial ports update in FreeBSD 12 r318838 AMD64 I'm 
getting some errors when rebuilding ports with this message:

  undefined reference to `kevent at FBSD_1.5'

Can anyone give a tip on what is causing this?


Thanks

[]'s

-Otacilio