This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
in the man page. ifconfig -au affects all interfaces marked as up,
and ifconfig -ad affects only the interfaces marked down. ifconfig -a
still handles everything. This change is purely for compatibility with
SunOS, for those who might be accustomed to the SunOS ifconfig's
behavior.
