all dependencies on packages depending on "png" which contain shared
libraries, all for the (imminent) update to the "png" package.
[List courtesy of John Darrow, courtesy of "bulk-build".]
differs from the distfile version number. G/C some the unused variables
in pdflib/Makefile.common related to the old way of handling version
numbers. Invent PDFLIB_BASE_VERS, which is ${PDFLIB_DIST_VERS} that's
been munged so that's understandable by the pkg_* tools' wildcard version
numbering logic.