Instead of manually adding both a build- and a run-time dependency on libedit from ports, use USES=libedit instead. Not only does it take care of adding the proper dependency, but it also sets CMAKE_PREFIX_PATH to ${LOCALBASE} to make sure that the version in ports is preferred instead of the one in base.
This is a dependency for moving to CMake 3.3.x, as starting with 3.3.0 calls to find_library() will also look in the $PATH environment variable and end up finding libedit from base by default.