audio_core: remove OpenAL sink implementation files

openal_sink.cpp (910 lines) and openal_sink.h (105 lines) are deleted.
OpenAL is the lowest-priority desktop audio backend; Cubeb and SDL2 cover
all the same platforms with better latency and reliability.

src/audio_core/sink/openal_sink.h

@@ -1,106 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#pragma once
-
-#include <string>
-#include <vector>
-
-#include "audio_core/sink/sink.h"
-
-namespace Core {
-class System;
-}
-
-namespace AudioCore::Sink {
-class SinkStream;
-
-/**
- * OpenAL backend sink, holds multiple output streams and is responsible for sinking samples to
- * hardware. Used by Audio Render, Audio In and Audio Out.
- */
-class OpenALSink final : public Sink {
-public:
-    explicit OpenALSink(std::string_view device_id);
-    ~OpenALSink() override;
-
-    /**
-     * Create a new sink stream.
-     *
-     * @param system          - Core system.
-     * @param system_channels - Number of channels the audio system expects.
-     *                          May differ from the device's channel count.
-     * @param name            - Name of this stream.
-     * @param type            - Type of this stream, render/in/out.
-     *
-     * @return A pointer to the created SinkStream
-     */
-    SinkStream* AcquireSinkStream(Core::System& system, u32 system_channels,
-                                  const std::string& name, StreamType type) override;
-
-    /**
-     * Close a given stream.
-     *
-     * @param stream - The stream to close.
-     */
-    void CloseStream(SinkStream* stream) override;
-
-    /**
-     * Close all streams.
-     */
-    void CloseStreams() override;
-
-    /**
-     * Get the device volume. Set from calls to the IAudioDevice service.
-     *
-     * @return Volume of the device.
-     */
-    f32 GetDeviceVolume() const override;
-
-    /**
-     * Set the device volume. Set from calls to the IAudioDevice service.
-     *
-     * @param volume - New volume of the device.
-     */
-    void SetDeviceVolume(f32 volume) override;
-
-    /**
-     * Set the system volume. Comes from the audio system using this stream.
-     *
-     * @param volume - New volume of the system.
-     */
-    void SetSystemVolume(f32 volume) override;
-
-private:
-    /// OpenAL device
-    void* device{};
-    /// OpenAL context
-    void* context{};
-    /// Device channels
-    u32 device_channels{2};
-    /// System channels
-    u32 system_channels{2};
-    /// Output device name
-    std::string output_device{};
-    /// Input device name
-    std::string input_device{};
-    /// Vector of streams managed by this sink
-    std::vector<SinkStreamPtr> sink_streams{};
-};
-
-/**
- * Get a list of connected devices from OpenAL.
- *
- * @param capture - Return input (capture) devices if true, otherwise output devices.
- */
-std::vector<std::string> ListOpenALSinkDevices(bool capture);
-
-/**
- * Check if this backend is suitable for use.
- * Checks if enabled, its latency, whether it opens successfully, etc.
- *
- * @return True is this backend is suitable, false otherwise.
- */
-bool IsOpenALSuitable();
-
-} // namespace AudioCore::Sink