Your package fails to build with the newest upcoming autoconf-2.71, which is part of a wide Fedora change. Please see the attached copr: https://copr.fedorainfracloud.org/coprs/odubaj/autoconf-2.70/packages/. More information about testing your package when building with autoconf available here: https://fedoraproject.org/wiki/Changes/Autoconf_271#How_To_Test
*** Bug 1943139 has been marked as a duplicate of this bug. ***
*** Bug 1943019 has been marked as a duplicate of this bug. ***
This isn't related to autoconf. The build fails the same way in rawhide.
It's related to two things with yelp-build html: 1. It needed -i to tell it that the image files aren't there but don't worry they will be 2. The output directory -o html now needs to be -o html/ or else it puts files one directory up. Anyway, building updates for rawhide and f34 now.