It's definitely building xpdf from the GIT tree. We need to apply all patches or pull the latest xpdf code. Note the numerous deprecation warnings associated with xpdf as well:
The primary issue then would seem to be that the internal Trinity xpdf is not being updated with security patches.
I don't know why we need a copy of xpdf to be honest. This needs to be looked into with an eye towards using the system xpdf libraries.
Tim