Add [[maybe_unused]] to silence unhelpful warnings

handlers/handlerversion.h

@@ -9,7 +9,7 @@ class HandlerVersion : public Handler
   public:
 	Response handleRequest(const Request &r) override;
 
-	bool canAccess(const Permissions &perms) override
+	bool canAccess([[maybe_unused]] const Permissions &perms) override
 	{
 		return true;
 	}