Add PipeWire audio driver

[j20001970]

Closes godotengine/godot-proposals#10723

This PR adds PipeWire audio driver for linuxbsd platform.

Distro support

This PR expects PipeWire version 1.0.0 or higher. Here is the non-exhaustive list of minimum Linux distribution version required for the driver to work.

Name	libpipewire-0.3.so version
Alpine v3.19	1.0.0
Debian 13	1.4.2
Fedora 38	1.0.3
openSUSE Leap 15.6	1.0.5
Ubuntu 24.04 LTS	1.0.5

How to test the driver

The new PipeWire audio driver does not take precedence over existing PulseAudio driver at the moment. You can change audio/driver/driver to "PipeWire" in Project Settings, or use --audio-driver PipeWire arguments to test the driver.

Vendored PipeWire headers

This PR introduces new thirdparty headers to enable PipeWire support. A brief list of added PipeWire and SPA headers as of version 1.0.0 (the list may change if we update the headers in future) is documented to give a better grasp on how these headers are included.

Required by "pipewire/pipewire.h":
|───"pipewire/array.h"
|───"pipewire/client.h"
|───"pipewire/conf.h"
|───"pipewire/context.h"
|───"pipewire/device.h"
|───"pipewire/buffers.h"
|───"pipewire/core.h"
|───"pipewire/factory.h"
|───"pipewire/keys.h"
|───"pipewire/log.h"
|───"pipewire/loop.h"
|───"pipewire/link.h"
|───"pipewire/main-loop.h"
|───"pipewire/map.h"
|───"pipewire/mem.h"
|───"pipewire/module.h"
|───"pipewire/node.h"
|───"pipewire/properties.h"
|───"pipewire/proxy.h"
|───"pipewire/permission.h"
|───"pipewire/protocol.h"
|───"pipewire/port.h"
|───"pipewire/stream.h"
|───"pipewire/filter.h"
|───"pipewire/thread-loop.h"
|───"pipewire/data-loop.h"
|───"pipewire/type.h"
|───"pipewire/utils.h"
└───"pipewire/version.h"

SPA headers required by PipeWire:
|───"spa/buffer/buffer.h"
|   └───"spa/buffer/meta.h"
|───"spa/node/command.h"
|───"spa/node/io.h"
|───"spa/node/node.h"
|   └───"spa/node/event.h"
|       └───"spa/pod/event.h"
|───"spa/param/param.h"
|   |───"spa/param/buffers.h"
|   |───"spa/param/port-config.h"
|   |───"spa/param/profile.h"
|   └───"spa/param/route.h"
|───"spa/pod/command.h"
|───"spa/pod/pod.h"
|───"spa/support/log.h"
|───"spa/support/loop.h"
|   └───"spa/support/system.h"
|───"spa/support/plugin.h"
|───"spa/support/thread.h"
|───"spa/utils/defs.h"
|───"spa/utils/dict.h"
|───"spa/utils/hook.h"
|───"spa/utils/list.h"
|───"spa/utils/string.h"
└───"spa/utils/type.h"

Headers required by `AudioDriverPipeWire`:
|───"pipewire/extensions/metadata.h"
|───"spa/param/audio/raw.h" <- for SPA_AUDIO_FORMAT_* and SPA_AUDIO_CHANNEL_* enum
|───"spa/param/format.h" <- for SPA_FORMAT_AUDIO_* enum
|───"spa/pod/builder.h" <- for spa pod builder related functions and macros
|   |───"spa/pod/iter.h"
|   └───"spa/pod/vararg.h"
└───"spa/utils/keys.h"

[Nintorch]

See also #109362 which may also add PipeWire support
Not to say your PR is worse or anything, just wanted to let you know about this PR too :)
But I'm not sure which one may be better or worse, or just different.

[j20001970]

I rebased the commits so that this PR no longer depends on #109500.

[j20001970]

9f33ab0 added PipeWire version check and changed headers version to 1.0.0, in sync with #109500.

[j20001970]

f1c07ca now uses print_verbose instead of ERR_FAIL_NULL_V macro if pw_context_connect failed in AudioDriverPipeWire::init, this is for suppressing errors on audio driver fallback when PipeWire library meets version requirement but the socket is not accessible.

[akien-mga]

Tested briefly on Fedora 43 (using PipeWire as audio server with default config) and it seems to work fine. I haven't reviewed the code yet.

How to validate that it's indeed using PipeWire directly and not via the pipewire-pulse plugin?

What kind of benefits are expected from this new driver, aside from sidestepping pipewire-pulse on systems defaulting to PipeWire?

Edit: I just read the proposal in godotengine/godot-proposals#10723. It mentions lacking audio input in ALSA, and too much latency in PulseAudio. Does this PR solve those two shortcomings?

---

Regarding the vendored headers in thirdparty/linuxbsd_headers/pipewire/, there's quite a lot of them. If possible, we like to trim down which thirdparty files we vendor to the minimum subset needed by Godot. I asked Copilot to assess which files could be safely removed and it came up with this: akien-mga@f8efbd3

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The downside is that we'd have to document which files should be copied / removed when updating the library.

[Damglador]

I check if a program is using pipewire directly by doing pw-dump > ~/pw-dump, searching for the program's binary name in the file and checking its "client.api", if there is no "client.api" for the program - it's using pipewire directly.

[j20001970]

What kind of benefits are expected from this new driver, aside from sidestepping pipewire-pulse on systems defaulting to PipeWire?

If I did the profiling correctly, we can expect the new driver having much lower driver time (audio_driver in EngineDebugger) when compared with existing PulseAudio driver, and the new driver also implements audio input that ALSA driver lacks, which should solve both issues mentioned in godotengine/godot-proposals#10723.

If possible, we like to trim down which thirdparty files we vendor to the minimum subset needed by Godot.

That makes sense, I'll try to trim down unused headers in next push.