You may be able to fix Kopete by switching USE flags off (my guess is that v4l2 is the guilty party here.)
Most of the others look like they may be genuine patch-required bugs related to recent changes in gcc/g++. Unfortunately, I don't use any of the packages involved except for kate-plugins, and I haven't needed to re-emerge it recently. It's possible that some packages might compile if you can figure out how to pass -fpermissive to the compiler (there's probably some way you can slip that into your make.conf, but I have no idea what it is--anyone?). It may be easier just to find non-KDE3 substitutes for the affected software, if you need the functionality it provides.
