updated unistd.h inclusion to be more aggressive

#endif

// Define max host name length

#if !defined(__APPLE__) && defined(__unix__)

// Some Linux environments require this, although not all, but it's benign.

#ifndef _BSD_SOURCE

    #define _BSD_SOURCE

#endif // _BSD_SOURCE

#include <unistd.h>

#endif  // __unix__

#ifndef HOST_NAME_MAX

    #define HOST_NAME_MAX 256

#endif // HOST_NAME_MAX