As outlined in [this
gist](https://gist.github.com/bbqtd/a4ac060d6f6b9ea6fe3aabe735aa9d95)
the version of `ncurses` shipped with macOS is too old to be aware of
the `tmux-256color` terminal info database which is the default in
`tmux`. This patch downloads the latest `ncurses` terminal info database
and uses that to install the `tmux-256color` entry for the current user
in `~/.terminfo`. This ensures that bold, italic, etc, are working
correctly and `git` does not throw warnings as noted
[here](1e2c00aa32)
