Emu: Convert Emu class to singleton

src/processing-unit.h

@@ -0,0 +1,14 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ * Copyright (C) 2022 Th3FrankXD
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+class ProcessingUnit {
+public:
+	ProcessingUnit();
+	virtual ~ProcessingUnit();
+};