This seems to be a build regression from ghc-8.0.1.

The ghc.1 manpage was not installed for the 8.0.2 RC1 build.

I reported this in mail earlier and unfortunately in the meantime lost the buildlogs on Fedora Copr, but since the upstream binary tarballs for Linux also don't seem to contain ghc.1 either it should not be too hard to reproduce.