NetBSD version is a feature-to-feature re-implementation of GNU
gzip using the freely-redistributable zlib and this version is
expected to be mostly bug-to-bug compatible with the GNU
implementation.
- Because this is a piece of mature code and we want to make
changes so it is added directly rather than importing to
src/contrib.
- Connect newly added code to src/usr.bin/ and rescue/rescue
build.
- Disconnect the GNU gzip code from build for now, they will
be eventually removed completely.
- Provide two new src.conf(5) knobs, WITHOUT_BZIP2_SUPPORT and
WITHOUT_BZIP2.
Tested by: kris (full exp-7 pointyhat build)
Approved by: core (importing a 4-clause BSD licensed file)
Approved by: re (adding new utility during -HEAD code slush)
