partly missing rpath information when building digikam5 for a parallel prefix

[René J.V. Bertin]

Hi,

I've been building Qt5 and KF5 for installation into a parallel prefix (/opt/local) that's not declared to ldconfig. I've had to figure out how to build Qt and configure KF5 applications such that full rpath information is stored, but that was neither very difficult nor did it require any patches.
I'm slowly expanding the number of KF5 apps I have installed this way, including pretty complex ones like KDevelop. I didn't have any issues with libraries not being found at runtime, until I installed digiKam5.

With that application, a number of Qt libraries are missing the required rpath information, while others are just fine. I don't know enough about the underlying mechanisms to troubleshoot this myself (and digiKam is a huge project that takes long minutes to process by `make` even if nothing has to be rebuilt). I do think it must be an issue in the buildsystem, probably something with the way the linker is invoked.

I've filed a report on BKO (https://bugs.kde.org/show_bug.cgi?id=365331) but there's not been any activity on that ticket since. Maybe someone here has an idea?

Thanks,
René