🚀 go-pugleaf

I am trying to derive a very simple class from TIdTCPClient but I get the
error

Unresolved external '__fastcall IdTcpclient::TIdTCPClient::SetPortA(const
int)' referenced from c:\...\unit2.obj.

Does anyone have any idea why I get this error ?

Here are the steps I take:
1) New Application
2) New Unit
3) The following code in the new unit (.H and .C)


              .H
//--------------------------------------------------------------------------
-
#ifndef Unit2H
#define Unit2H
//--------------------------------------------------------------------------
-
#include <winsock2>        // just to cover for multiple fd_set error
#include <IdBaseComponent.hpp>
#include <IdComponent.hpp>
#include <IdTCPClient.hpp>
#include <IdTCPConnection.hpp>

class TTest : public Idtcpclient::TIdTCPClient
{
public:
  __fastcall virtual TTest(Classes::TComponent* AOwner);
};
#endif


        .C
//--------------------------------------------------------------------------
-
#pragma hdrstop
#include "Unit2.h"
//--------------------------------------------------------------------------
-
#pragma package(smart_init)
__fastcall TTest::TTest(Classes::TComponent* AOwner) : TIdTCPClient(AOwner)
{
};