service: add os types and multi wait API

src/core/hle/service/os/event.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+namespace Kernel {
+class KEvent;
+class KReadableEvent;
+} // namespace Kernel
+
+namespace Service {
+
+namespace KernelHelpers {
+class ServiceContext;
+}
+
+class Event {
+public:
+    explicit Event(KernelHelpers::ServiceContext& ctx);
+    ~Event();
+
+    void Signal();
+    void Clear();
+
+    Kernel::KReadableEvent* GetHandle();
+
+private:
+    Kernel::KEvent* m_event;
+};
+
+} // namespace Service