Add a build recipe for qbzd, the Qobuz Connect renderer

[Gjuju]

Builds qbzd from PhilipVinc's moOde-targeted tag (qbzd-v2.0.2.moode49), same
shape as the librespot recipe.

Upstream packages for Arch, snap and Flatpak but ships no Debian metadata, so
the [package.metadata.deb] section is added by a patch. Only the qbzd crate is
built -- the slint-free column of the workspace -- so none of the desktop GUI
stack is linked.

cargo jobs are budgeted from RAM rather than core count: 512 MB kept aside for
the system, then 512 MB per job, capped at nproc. This workspace is heavier
than librespot and its last crates are the hungry ones -- on a 1 GB board two
jobs thrash the card until the system stops answering and systemd's watchdog
resets it. Measured while building this package: 990 MB of swap at peak with a
single job.

Verified through the on-demand plugin chain, from boxes with no qbzd installed:

• Orange Pi 3 LTS (2 GB, -j2): 439 crates, 82m15s
• Raspberry Pi 3B (905 MB, -j1): 430 crates, 137m14s
  Both install cleanly and report qbzd 2.0.2.moode49.

One note on the librespot recipe it is modelled on: its two error paths end on
a bare exit, which returns 0, so a failed build looks successful to the
plugin script. This recipe uses exit 1.

[Gjuju]

@moodeaudio

One naming question: the package comes out as qbzd_2.0.2-1moode1 while the binary reports 2.0.2.moode49, upstream's build id for the tag we clone.

Would you rather they matched -- qbzd_2.0.2.v49-1moode1, say?

It's one line here plus one in moode-sqlite3.db.sql, and I'm happy either way -- your call on naming.

[moodeaudio]

I think @PhilipVinc said he wants to create a new repo name and release tag scheme at some point and so I would recommend simplifying things for this initial test package build and not entangling separate version or build vars.

Maybe something like this where the build number "49" is in the package name.

PKG="qbzd_2.0.2-49-1moode1"
PKG_SOURCE_GIT="https://github.com/PhilipVinc/qbz.git"
PKG_SOURCE_GIT_TAG="qbzd-v2.0.2.moode49"
export QBZD_BUILD_ID="2.0.2.moode49"

This will be good for local testing. I'm not planning to release this as an official plugin until the repo name and release tag format is settled.

[PhilipVinc]

I will be dropping the .moodeXX flags, and switching to a standard versioning scheme.
I will be renaming the package as well and cleaning up the repository to remove all cruft/gui stuff that was inserted from qbz .

I've done most changes locally, and testing a new build that is more reliable than the previous one.

I'll take care of the build recipe myself when I feel confident enough that things settled. I think mid week, probably.

[PhilipVinc]

I think you'll have something like

mu-qbzd 3.0.0
or
pi-qbzd 3.0.0

when I'm done

[Gjuju]

Done, thanks.

As a temp solution :

Package now builds as qbzd_2.0.2-49-1moode1_arm64.deb.
dpkg-deb reads it back as Version: 2.0.2-49-1moode1.

One note: cargo-deb builds the version from the crate version plus a revision, and a revision can't hold the build number (no hyphens), so it goes through --deb-version instead.
That supersedes the revision, so the sed that used to patch it into Cargo.toml is no longer needed and is gone.

For local testing, cfg_plugin.version has to match the new name or the plugin looks for the old file.