[Fedora-packaging] Using newish rpm features in Fedora buildsys

Hi, I ran into a "make srpm" issue in the buildsys (again, seen them before every now and then) because I was using a feature in the specfile that is not supported by the version of rpmbuild that gets run with "make srpm" there. https://fedorahosted.org/fedora-infrastructure/ticket/817 I suppose there are a lot of contributors that are not aware of this, so it (along with some details exactly what to expect to (not?) work, maybe from someone from the infrastructure team who knows the details) could be a worthy addition to somewhere in the package maintainers documentation section in Wiki. Main packaging guidelines?