I think this problem has now gone away on my machine.  I cannot be sure what
it was that helped.  I removed all qt-* packages, and some of the
problematic packages mentioned as depending on the earlier versions.  After
running

     # emerge -utv world, I noted some dependencies, and may have removed
one or two.  Then I ran the install.

After a couple of interations, all *seems* to be well.

Thank you for the advice,

Alan Davis