The issue looks to be lensfun... what version of that did you install?
Going by the bug report, you need 0.2.7 for the new digikam build to work with it.
If you go here:
get the new version of lensfun
Assuming you are using the slackbuild from here:
It's usually just an edit to bump the version number and rebuild, then upgradepkg on lensfun and try building digikam again.
If you don't want lensfun, it looks to be optional, so you can removepkg on it and just build digikam without it.. always your choice.