When you make a Geant4.9.5 application using the traditional "make" method, not cmake, probably you will meet this error message:
error: qobject.h: No such file or directory
Here I will give two solutions to it.
First,
add below lines in your GNUmakefile:
INCPATH := -I/usr/include/qt4/Qt -I/usr/include/qt4
CPPFLAGS+= $(INCPATH)
to tell the compiler where the qt headers are.
But this is not a good method, because you have to add them for every application.
Second,
add below lines in your .bashrc file. (for .cshrc, it's similar, but not exactly the same)
export QTMOC="/usr/bin/moc-qt4"
export QTFLAGS="-I/usr/include/qt4 -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4/QtOpenGL"
export QTLIBS="-L/usr/lib -lQtCore -lQtGui"
export GLQTLIBS="-L/usr/lib -lQtCore -lQtGui -lQtOpenGL"
After setting this, you will not see the error message when using qt gui in your application.