Mouse follow focus on OSX

I always configure my Linux window managers to use "focus follow mouse". Meaning, whichever window the mouse cursor is currently in, gets keyboard focus. This is not possible with most OSX applications, because of how they've designed the UI with one Menu bar etc. However, at least two apps. Terminal and the X11 server, can be configured to do just this. It's really easy:

$ defaults write org.x.X11 wm_ffm -bool true
$ defaults write FocusFollowsMouse -string YES