CPack + Qt IFW, QIFWDIR environment/CMake variable

[Pl45m4]

I'm messing around with the Qt Installer Framework and CPack, for a private project and for the sake of understanding.

I watched the Qt Summit Video presented by Christopher Probst as well as the written guide on ICS

• https://www.youtube.com/watch?v=3xuq985YKI0
• https://www.ics.com/blog/revisiting-qt-installer-framework-cmake

The part on how to intergrate Qt IFW into CPack says that it is necessary to set a bunch of variables in CMake like

set(CPACK_GENERATOR "IFW")

OR (as used in the guide):

set(CPACK_IFW_ROOT "C:/Qt/Tools/QtInstallerFramework/4.1/") #QTIFWDIR is used by default

Of course the hard coded path is not the cleanest way, but as mentioned in the comment QTIFWDIR is used as CPACK_IFW_ROOT.
However, none of these variable are set/present in my default configuration... not in CMake and not in my system's environment variables after installing the Qt Installer Framework (ver. 4.8).

I looked it up in the CMake manual

• https://cmake.org/cmake/help/latest/cpack_gen/ifw.htm
• https://cmake.org/cmake/help/latest/cpack_gen/ifw.html#hints-for-finding-qtifw

which also mentions these variables (QTIFWDIR can be both, a CMake and environment variable).

But how to set all this? Manually? This can't be the solution :D
Did I miss something when installing the Installer Framework?

At some point you have to provide a path to the location of Qt IFW, right? I don't see any CMake or environment variable in my config which points to the correct directory.

Any help appreciated :)