Cmakelist missing Boost_SYSTEM_LIBRARY

[bananamacs]

I'm aware this project is possibly not actively maintained so sorry to dredge it up, but when I tried to compile on osx the build failed due to a missing refence to boost::system::generic_category. including system in the find_file section and "{Boost_SYSTEM_LIBRARY}" to the target_link_libraries section of the Cmakelists.txt fixed it for me and the included tests pass, albeit compilation spits out a ton of warnings about empty macro arguments or some such thing.