When USE'ing localbase.mk, make sure CMake is also aware that it is supposed to give preference to ${LOCALBASE} when looking for files and libraries.
This is going to be a requirement once CMake is updated to 3.3.0, as starting with this version it will by default use the PATH environment variable (stripping the "/bin" or "/sbin" parts of each entry) to determine where to find files and libraries. Since in most cases /usr will come before /usr/local, it will find base's libarchive and fail at the configuration stage on older FreeBSD releases.