Please apply this patch https://reviews.freebsd.org/D14558 to net-im/tox, and update the port to the later version that supports the new toxcore. Thank you, Yuri
My attempt to build the current version of uTox (0.16.1-208-g3b3bc91f) failed: https://github.com/uTox/uTox/issues/1189 It appears that uTox is broken.
As remarked by Yuri, there is a disagreement in uTox about toxcore 0.2.0: see https://github.com/uTox/uTox/pull/1157 In the meantime, net-im/tox has been repocopied to net-im/tox12, and uTox now depends on this legacy version.