Can't install Ettercap with Graphical mode using Homebrew

To install Ettercap with the graphical mode with Homebrew, you can use the option --with-gtk+

$ brew install ettercap --with-gtk+

For your own information, you can get details about options on any Homebrew formula with brew info [formula]

Issuing brew info ettercap in the Terminal will show something like

ettercap: stable 0.8.0, HEAD
http://ettercap.github.io/ettercap/
/usr/local/Cellar/ettercap/0.8.0 (69 files, 2,1M) *
  Built from source with: --with-gtk+, --with-ipv6
From: https://github.com/Homebrew/homebrew/commits/master/Library/Formula/ettercap.rb
==> Dependencies
Build: cmake ✔, ghostscript ✘
Required: pcre ✔, libnet ✔, curl ✔
Optional: ghostscript ✘, gtk+ ✔, luajit ✘
==> Options
--with-ghostscript
    Build with ghostscript support
--with-gtk+
    Build with gtk+ support
--with-ipv6
    Install with IPv6 support
--with-luajit
    Build with luajit support
--without-curses
    Install without curses interface
--without-plugins
    Install without plugins support
--HEAD
    install HEAD version

Note: in order to use this graphical mode, you also need to install XQuartz