Fix unexpected exit when call in escript on macOS

[marocchino]

Because, fsevent_fetch use relative path. It can not resolve from {cd, Cwd}. So, it sould be absolute path or remove cd part from here.

It will be happen only macOS. because, It is only one that use relative path.

13:18:58.897 [error] GenServer :watcherfile terminating
** (stop) {:port_exit, 2}
Last message: {#Port<0.3106>, {:exit_status, 2}}
State: {:state, :watcher, #Port<0.3106>, "/Users/user_name/Documents/test-project/", :fsevents}

[Dalgona]

FYI there is a brew package called fsevent_watch which installs the exactly same program as mac_listener. Maybe we can detect and use that one?