CMake fails to add the library path for lz4 to the linker script. This causes an issue during linking where -llz4 fails.
Adding the path to `liblz4.so` to link.txt fixes the issue for me.
`LOCALBASE` in FreeBSD is set to /usr/local and liblz4 is installed there.
Detection of lz4 is apparently OK otherwise the code in CMakeLists would return an error.