"first defined here" error when linking to boost::process 0.6

I am a bit lost with this linking error, I assume the problem lies on my side rather than in the lib itself but I don't know how to solve this.

I am trying to link to boost::process 0.6 http://ift.tt/2cH49IU

        CMakeFiles/http://ift.tt/2csNzJs: In function `boost::process::detail::posix::cmd_setter_::make_cmd(std::vector<std::string, std::allocator<std::string> >&)':
        recorder.cpp:(.text+0x11c): multiple definition of `boost::process::detail::posix::cmd_setter_::make_cmd(std::vector<std::string, std::allocator<std::string> >&)'
        CMakeFiles/http://ift.tt/2cH3OpF: first defined here
        CMakeFiles/http://ift.tt/2csNzJs: In function `boost::process::detail::posix::exe_cmd_init::make_cmd()':
        recorder.cpp:(.text+0x1fc): multiple definition of `boost::process::detail::posix::exe_cmd_init::make_cmd()'
        CMakeFiles/http://ift.tt/2csOrxq: first defined here
        CMakeFiles/http://ift.tt/2csNzJs: In function `boost::process::detail::posix::async_pipe::operator=(boost::process::detail::posix::async_pipe&&)':
        recorder.cpp:(.text+0x316): multiple definition of `boost::process::detail::posix::async_pipe::operator=(boost::process::detail::posix::async_pipe&&)'
        CMakeFiles/http://ift.tt/2cH2ZNv: first defined here