tmux-2.4-2byte
2byte文字やら全角やらでパッチを当ててるやつ書いてくれてる人がいましたので。
http://attonblog.blogspot.jp/2017/04/full-width-tmux-2-4.html
$ brew tap atton-/customs
$ brew edit atton-/customs/utf8proc
$ brew install atton-/customs/utf8proc
$ brew edit atton-/customs/tmux
$ brew install --HEAD atton-/customs/tmux