To build KDE4, do I have to have Qt3 *and* Qt4 installed? I'm getting
a ./configure error when compiling trunk/arts:

checking for Qt... configure: error: Qt (>= Qt 3.3 and < 4.0) (headers and
libraries) not found. Please check your installation!

As far as I know, arts as it is now, will not be used in kde4 anymore.

If there are still programs in trunk which need it, do a configure with the option --without-arts

On the other hand, kde4 does not exist yet. There's only svn trunk wich will eventually be kde4.

At the moment, developers are porting trunk to use qt4 and make it compile and link.

In other words, in the end, trunk will completely use qt4, as far as I understand it.

So, anything in trunk wanting to use qt3 still needs to be converted.