It would be nice to support RichDependencies in build system. This has been introduced in rpm-build-4.12.90-7.fc24.x86_64 The version of that rpm is now in rawhide so it should be used automatically. Main problem is that we need that version on copr-dist-git machine too. And that is running RHEL7 so we either migrate that machine to rawhide (just kidding) or we try to rebuild that version of rpm for RHEL7 and use it on that machine (needs a lot of testing).
RichDependencies are supported now.