[cpp] freeaddrinfo 사용 시 주의해야 할 점

http://msdn.microsoft.com/en-us/library/ms737931(VS.85).aspx

The freeaddrinfo function was added to the Ws2_32.dll on Windows XP and later. To execute an application using this function on earlier versions of Windows (Windows 2000, Windows NT, and Windows Me/98/95), then you must include the Ws2tcpip.h file and also include the Wspiapi.h file.

간단번역: freeaddrinfo는 Windows XP 이후에 추가 했으니, 그전 운영체제에서 사용하려면 ws2tcpip.h는 물론 wspiapi.h를 포함시키렴.