> * Usage: user prepends "--bzip2-filter=lbzip2" to her TAR_OPTIONS.
> * On Debian, the tar source could be patched, so that "bzip2_filter"
> defaults to "/etc/alternatives/bzip2-filter", which would be a symlink to
> /bin/bzip2 per default. Packages like "lbzip2" and "pbzip2" would add
* User sets specific options for her choice of bzip2-filter by setting
appropriate environment variables. For example,