Description of problem: Please refer to the thread at the URL above. My FE package blogtk-1.1-4.fc4 was built for i386 containing files where %{_libdir} evaluated to /usr/lib64. Replies in the thread seem to give possible solutions by changing the contents of /etc/rpm/platform, although I am not in a position to judge whether any of the solutions are workable for the FE build systems.
This is my fault and no one else's. The fedora-rpmdevtools' Python spec file template has guidance that nixes this problem. I will revise my package to use the template properly and that should eliminate the problem.