ifconfig with no args should list all interfaces
It's 2012 and high time for ifconfig without arguments to default to the same behaviour that every other modern UNIX platform exhibits. That is: ifconfig should print a list of all interfaces as if the user had typed ifconfig -a.
This change will not alter any other existing behaviour, including preserving the behaviour of -a without other arguments. It will bring us into line with at least the following other platforms: OpenBSD, Mac OS X, Linux.