audio_core: Implement OpenAL backend (#6450)

src/audio_core/openal_sink.h

@@ -0,0 +1,30 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <cstddef>
+#include <memory>
+#include <string>
+#include "audio_core/sink.h"
+
+namespace AudioCore {
+
+class OpenALSink final : public Sink {
+public:
+    explicit OpenALSink(std::string device_id);
+    ~OpenALSink() override;
+
+    unsigned int GetNativeSampleRate() const override;
+
+    void SetCallback(std::function<void(s16*, std::size_t)> cb) override;
+
+private:
+    struct Impl;
+    std::unique_ptr<Impl> impl;
+};
+
+std::vector<std::string> ListOpenALSinkDevices();
+
+} // namespace AudioCore