For building Qt you don't need any settings. Just invoke the qmake of your "source-directory" only after successfully build it you must tell the application you are going to build which qmake to use. You can do it over your ~./profile, create new symbol links or simply call the qmake with the full path. That on your system are also qmake-qt3 is no problem at all. Just make sure, that a simple "qmake" in your console reaches the right qmake. (I'd preferre the ~/.profile approach.)