building libgstfragmented in 1.4.3

[alicewonder at shastaherps.org]

Building gstreamer1 1.4.3 via rpm for CentOS 7

Building the plugins-bad

On my system outside of mock the libgstfragmented.so is built but inside 
mock it is not.

Clearly my spec file is missing a BuildRequires but I can't seem to find 
what it is (nothing is installed on my system that isn't available to  the
mock build environment)

Any suggestions on how I might track that down?

Thanks