Before starting the Qt5/KF5 port, apply this patch as the first when
having branched off the branch where the port work shall happen. It
will help controlling what is build and what not, using all the powers
of the product set system. No need to uncomment all kind of cmake lines
and mess with internal deps, just control by the "UNPORTED" tags.

It will remove all products/features from the build which have the tag
"UNPORTED" in their definition right after the name (at least before
the "REQUIRES" section). Initially this patch will set the tag to all
products & features, so that the stuff to build after running cmake will
be an empty list.

So once you start working on the port of another product, remove the
"UNPORTED" tag for it, so it gets into the list of things to build. To
overrule/ignore the "UNPORTED" tags, pass -DBUILD_UNPORTED=1 to cmake.

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