Dynamically load FFmpeg and libfdk-aac if available. (#6570)

src/common/dynamic_library/dynamic_library.h

@@ -0,0 +1,39 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+#include "common/common_types.h"
+
+namespace DynamicLibrary {
+
+class DynamicLibrary {
+public:
+    explicit DynamicLibrary(std::string_view name, int major = -1, int minor = -1);
+    ~DynamicLibrary();
+
+    bool IsLoaded() {
+        return handle != nullptr;
+    }
+
+    std::string_view GetLoadError() {
+        return load_error;
+    }
+
+    template <typename T>
+    T GetSymbol(std::string_view name) {
+        return reinterpret_cast<T>(GetRawSymbol(name));
+    }
+
+    static std::string GetLibraryName(std::string_view name, int major = -1, int minor = -1);
+
+private:
+    void* GetRawSymbol(std::string_view name);
+
+    void* handle;
+    std::string load_error;
+};
+
+} // namespace DynamicLibrary