This works fine for me: $ qmake -query QT_INSTALL_PREFIX /usr $ qmake -query QT_INSTALL_BINS /usr/bin
qt4-qmake 4.5.0-0ubuntu4
This works fine for me:
$ qmake -query QT_INSTALL_PREFIX
/usr
$ qmake -query QT_INSTALL_BINS
/usr/bin
qt4-qmake 4.5.0-0ubuntu4