Fix " /usr/bin/ld: cannot find -lGL " in QT in Ubuntu
for this problem, just add this one than one in terminal:
sudo apt-get install libqt5concurrent5
sudo apt-get install libqt5test5
sudo apt-get install libqt5core5a
sudo apt-get install libqt5opengl5
sudo apt-get install qtdeclarative5-dev source: link