Instead of generating
QT.KArchive.includes = /full/path/include/KF5/KArchive
make it
QT.KArchive.includes = $$PWD/../../include/KF5/KArchive
This makes the whole install prefix relocatable after the fact,
the includes will be found based on where the .pri file ended up.
This is especially useful for Conan support, says Bogdan.