gian@gian-Latitude-D630:~/build$ make
/usr/lib/x86_64-linux-gnu/qt4/bin/uic ../GuitarSynth/mainwindow.ui -o ui_mainwindow.h
/usr/lib/x86_64-linux-gnu/qt4/bin/uic ../GuitarSynth/SynthBase.ui -o ui_SynthBase.h
g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++-64 -I../GuitarSynth -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I../GuitarSynth -I. -o main.o ../GuitarSynth/main.cpp
g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++-64 -I../GuitarSynth -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I../GuitarSynth -I. -o mainwindow.o ../GuitarSynth/mainwindow.cpp
In file included from ../GuitarSynth/synthbase.h:21:0,
from ../GuitarSynth/squaresynth.h:19,
from ../GuitarSynth/mainwindow.cpp:19:
../GuitarSynth/synthcontrol.h:21:27: fatal error: QtWidgets/QDial: No such file or directory
#include <QtWidgets/QDial>
^
compilation terminated.