There is a section in Makefiles.defs regarding freebsd. Here we can see that the resolv library is not added to the LIBS. Regarding the locking method, I think freebsd just uses fastlock if executed on a standard architecture (e.g. x86, x86_64). Here the file section [link](https://github.com/kamailio/kamailio/blob/6b0b8cb84b7d0e965d50bdf0dfa5423004...)