The build craps out with lots of errors about unpackaged files. All of these files are generated by the debuginfo magic though.
It seems they did some changes to this system in Fedora 27:
Something is very strange here. I should be able to disable this new feature doing:
However that still fails with rpm complaining about the debug symbol file being unpackaged. It is however completely content with all the source code files. And both of these things are defined in the same debugfiles.list, so I have no idea why one works and the other doesn't.
I tried rebuilding a normal Fedora package with debugsource turned off and that worked fine, so it is possible to turn it off.
Need to get this sorted now so we can upgrade things for the next release.
The problem is that they've added a lot of checks for "noarch" inside the rpmbuild binary now. Previously those checks were all in the macros so we could override them.
Fortunately it is possible to disable this new feature completely, which makes our builds work again (until they add even more checks).
However, there is one more change as part of this. We're no longer build-id symlinks in /usr/lib/debug. That code has also gotten a noarch check that we cannot bypass. Because of this we probably need to turn off decorated debug file names so that tools such as gdb can still find the debug symbols.
Builds are working fine now Fedora 27.
I successfully built 11 packages on my fedora 28 workstation. Looks good.