OpenSystemsDevelopment / qpdf

Fix pkg-test CI Failure on using <concepts> include file.

* Define POINTERHOLDER_TRANSITION
* Make sure we are getting the intended version of qpdf

Run this:

for i in  **/*.cc **/*.c **/*.h **/*.hh; do
  clang-format < $i >| $i.new && mv $i.new $i
done

Also add a pkg-config runtime test that would have caught the error.