Older libc++ releases have a bug, https://reviews.llvm.org/D107199, that prevents connectSingleShot() in this port from working in certain cases. The current workaround was to just avoid compiling the test that caused the build to fail, but it does not fix the problem for consumer ports like net-im/neochat.
The easiest solution in this case is to make the port fall back to a code path that does not use std::bind_front() on FreeBSD versions with older LLVM releases.