[CMake] Qt - Private implementation slot and required cmake special rules

[Olaf Peter]

I try to use Qt's internal Stuff for my own purpose. I want to compile
the moc file separately which is with cmake very simple. Anyway, I have
to tweak moc for this.

I have to add the private type to the moc file generated otherwise I get
an compiler error about incomplete type (the "public" header forwards
only the private), in this case simple by e.g.

/usr/bin/moc-qt4 -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED
-I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore
-I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. slotTest.h
-fslotTest_p.h -o moc_slotTest.cpp

Note the -fslotTest_p.h

Now I've the private header included, but how to say this for cmake for
the general case?? QT4_WRAP_CPP allows addition options, but how to get
the private header?

Thanks,
Olaf