The main reason is that sope4 without any zeroconf mechanisms (either avahi or mdns) does not pull in libiconv while it is still being referenced in makefiles.
poudriere log with avahi:
Poudriere log without avahi:
The other possible solution would be to tweak sope-core/NGExtensions/GNUmakefile.preamble to not depend upon -liconv on FreeBSD.
Yes, but sope4 still refers to the external one. The other way around would be to patch the build bits to not look for -liconv or better, to find out why is it still trying to use -liconv