libgexiv2 currently fails to build, https://koji.fedoraproject.org/koji/buildinfo?buildID=885804 I suspect it is related to a recent introduction of exiv2-0.26 to rawhide.
This is due to: http://dev.exiv2.org/issues/1175
Built libgexiv2-0.10.5-3.fc27: https://koji.fedoraproject.org/koji/taskinfo?taskID=19489267
Thanks for the detective-work