Why not drop global useflags entierly?

There really is no reason for them. Extend euse to modify
/etc/portage/packages.use.

I think it is time to begin decentralizing the system now. Portage is
getting rather large and will probably be broken up into pieces in the
future. If ebuilds didn't have to concider some global useflag namespace
it would be eaiser to sync diffrent vendors trees.

-John