Saw another user reporting a problem I had quite a while ago on the forums [1] that was also reported on gentoo and now fixed [2]. Applying the gentoo fixes [3][4] made the package compile without errors.

Added are my own `emerge --info` output, the build.log from me trying to compile earlier and the cmake-utils.eclass file with the fixes from gentoo that made the package compile without errors.

[1] https://forums.funtoo.org/topic/1601-media-libsvulkan-loader-10540-failed-to-build/

[2] https://bugs.gentoo.org/625844

[3] https://gitweb.gentoo.org/proj/kde.git/commit/eclass/cmake-utils.eclass?id=460ffd9c15ee42497bf7a802d097915b71479dd8

[4]  https://gitweb.gentoo.org/proj/kde.git/commit/eclass/cmake-utils.eclass?id=f73d21cbe6317ec0baa2858a4ce4ead72dc7b832