I discovered in the course of installing Evince, the new PDF viewer
for GNOME, that the FreeDesktop folks now endorse the "poppler"
PDF-management library, which is a stand-alone library created out of
xpdf's code. It would be very sensible for ViewPDF to be based on
that, because it will be easier than including all of xpdf's source,
and updates (including security patches) will be more frequent. Evince
renders the vast majority of my PDFs very well, so I think ViewPDF can
make the change with no drawbacks.