Mentor import done.

src/system/pins.hpp

@@ -2,13 +2,19 @@
 #define _PINS_HPP_
 
 #include "syselmts.hpp"
-#include "signals.hpp"
+
+#pragma once
+class Part;
+
+#pragma once
+class Signal;
 
 class Pin : public SystemElement
 {
     Signal *sig;
 public:
     Pin(std::string name);
+    Part *prnt; ///< Pointer to the parent part.
     bool connected();
     void connect(Signal *signal);
 };