Since unfortunately some of the autogenerated includes don't pass the
checks we do a trick of building out of source and then specifying the
.*/okular/.* path as the only includes we care about
This seems to be required with KPluginFactory and Qt5 since without it
KPluginFactory::create<Okular::Generator>() always returns null.
For some reason this requires a complete rebuild before generatorstest
passes.
REVIEW: 123466