The package rpms/nbc.git has added or updated architecture specific content in its spec file (ExclusiveArch/ExcludeArch or %ifarch/%ifnarch) in commit(s): http://pkgs.fedoraproject.org/cgit/rpms/nbc.git/commit/?id=37cfc75d8bb1f0aea....
Change: +ExclusiveArch: %{arm} %{ix86} x86_64 ppc ppc64
Thanks.