How do we build a project with qmake-qt4?

After few adjust to correctmodule directories in migration qt4 project to qt5, then stumbeld on:


g++ -c -pipe -O2 -D_REENTRANT -flto -fno-fat-lto-objects -Wall -Wextra -fPIC -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_XML_LIB -DQT_CORE_LIB -I. -Ibuild -I/usr/include/qt -I/usr/include/qt/QtGui -I/usr/include/qt/QtXml -I/usr/include/qt/QtCore -Ibuild -I/usr/lib/qt/mkspecs/linux-g++ -o build/main.o src/main.cpp
In file included from src/mainwindow.h:33,
from src/main.cpp:30:
src/databook.h:33:10: fatal error: QtWidgets: No such file or directory
33 | #include <QtWidgets>


Please help !

Edit:
this after modifying

.pro fiie added ):

Code:

---

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

---

in main.cpp

and and find QWidget, QLabel,, QTreeWidget, QtGui

but finally hit that hardest part problem to solve, so ask help again