From Fedora Project Wiki
Bundled Software policy
This policy concerns the use of bundled software in the Fedora Package Collection.
Policy
All packages whose upstreams allow them to be built against system libraries must be built against system libraries.
All packages whose upstreams have no mechanism to build against system libraries must be contacted publicly about a path to supporting system libraries. If upstream refuses, this must be recorded in the spec file using a persistent mechanism to be clarified in the packaging guidelines.
All packages whose upstreams have no mechanism to build against system libraries may opt to carry bundled libraries, but if they do, they must include Provides: bundled(<libname>) = <version> in their RPM spec file.