dev-tcltk/expect have two possible flags, X and doc, the only dependency involved by the X flag is dev-lang/tk, so I suggest dev-tcltk/expect will depend on dev-lang/tk when the tk flag is enable, not the X one.
That's actually wrong, USE="-tk" does myconf="$myconf --without-x"; we don't name use flags after dependencies but after what they actually do with functionality.
Well, I have the X flag enable in my make.conf and I noticed that time that for example on my system, 'expect' was the only reason 'tk' was installed on it. Since most of people have the X flag in their make.conf, I thought it would be a good idea to rename the flag. But nevermind.
