Add an ACL list for users connecting to the tmux socket. Users may be

Add an ACL list for users connecting to the tmux socket. Users may be
forbidden from attaching, forced to attach read-only, or allowed to
attach read-write. A new command, server-access, configures the list.
tmux gets the user using getpeereid(3) of the client socket. Users must
still configure file system permissions manually. From Dallas Lyons and
others.