You should not need to set QTDIR because it should already been automatically
configured (in '/etc/profile.d/qt4dir.sh' and '/etc/profile.d/qt4dir.csh').

To check if it is the case, do 'echo $QTDIR'. Answer should be '/usr/lib/qt4'.

If it is not the case, do 'export QTDIR=/usr/lib/qt4' if you use bash or
'setenv QTDIR /usr/lib/qt4/' if you use csh.

Qt documentation is in /usr/share/doc/qt-4.8.6/ (you need to
install package qt4-doc-4.8.6-alt3.M70P.1 if it is not already
done).

Other Qt things are in /usr/lib/qt4/ (which contains needed symlinks
to create a fake QTDIR).

Examples and tutorials are compressed to save space. If you want to use them,
you need to uncompress them somewhere in your home directory using:
'cd your_directory; tar xvfj /usr/share/doc/qt-4.8.6/examples.tar.bz2'.

You may override placement of ~/.config/ directory with settings files
by exporting XDG_CONFIG_HOME variable before start Qt-based application.
