"extract" script for extraction. Many cases where a custom EXTRACT_CMD
simply copied the distfile into the work directory are no longer
needed. The extract script also hides differences between pax and
tar behind a common command-line interface, so we no longer need code
that's conditional on whether EXTRACT_USING is tar or pax.
This was suggested by David Griffith on tech-pkg. Enjoy!
psjoin concatenates several PostScript files (complying with the
Document Structuring Convention, DSC) and generate a single PostScript
document. The concatenated PostScript document will be written to
the standard output.