Adding pkg_summary.xz (Was: Preferring .gz with pkgin)

[David Brownlee <abs%absd.org@localhost>]

On Tue, 12 Oct 2021 at 12:54, Jonathan Perkin <jperkin%joyent.com@localhost> wrote:
> [...]
> Sorry, I hadn't realised that the default pbulk still didn't produce
> pkg_summary.xz files (I've been doing this for Joyent packages since
> 2015), so I'll leave bzip2 alone for now.

tl;dr - replace pkg_summary.bz2 logic in scripts/binpkg-cache with
pkg_summary.xz

Would anyone object to replacing the logic to build pkg_summary.bz2
with matching logic to build pkg_summary.gz. Note that pkg_summary.gz
is always built, and this is only affecting the second optional
compression format.

scripts/binpkg-cache only updates pkg_summary.bz2 if it already
exists, so this will not affect anyone who has not previously created
a pkg_summary.bz2. I'd also like to add a line to warns about any
orphaned pkg_summary.bz2 files (or event abort with an error at that
point)

David