Rob, Thanks for the advice. I tried the modification suggested. It allowed the module to be made and installed, but when I use it to load a pdf file, it throws an error. So, I think there is some defect in how the wrapper is linking to the underlying library.
I now see from CPAN testing reports that testers had the same problem. I emailed the author asking if he would suggest a correction ... I don't have nearly the skills needed to tinker with XS. Hopefully he will address because I think that module would be very useful.
Thanks again!