Question: how to install qwt in qt 5?
Answer: cd qwt-6.1.5. /usr/local/Qt-5.0.1/bin/qmake qwt.pro. ...  make. ( On multicore systems you can speed up building the Qwt libraries with running several jobs simultaneously: f.e. "make -j4" on a dual core. ) ...  sudo make install. ...  cd qwt-6.1.5. ...  mingw32-make. ...  mingw32-make install. ...  nmake. ...  nmake install.