Adding pkg-config files to a library allows other programs to find the information needed to successfully compile against the library much more easily than by using traditional means. I don't see any method for programs to find out compilation and linking flags in crypto++-5.6.0. Adding these should hopefully be trivial.
Thanks for the suggestion.
Can you comment at "Distro maintainers: pkg-config and DataDir patch?", https://groups.google.com/forum/#!topic/cryptopp-users/VqPmjsxJBVE?