"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.
module directory has changed (eg. "darwin-2level" vs.
"darwin-thread-multi-2level").
binary packages of perl modules need to be distinguishable between
being built against threaded perl and unthreaded perl, so bump the
PKGREVISION of all perl module packages and introduce
BUILDLINK_RECOMMENDED for perl as perl>=5.8.5nb5 so the correct
dependencies are registered and the binary packages are distinct.
addresses PR pkg/28619 from H. Todd Fujinaka.
