These includes must be available on any Un*x, Windoze and Mac Donald's

#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/time.h>
#include <fcntl.h>
#include <sys/utsname.h>

Please look also into *all* your systemwide "socket.h" and the header
files (mainly in /usr/include/sys or krnl-src) included by them for 
declarations like "MSG_PEEK" etc.
In case of missing MSG_foo declarations please contact me:

Oliver Delise  <delise@mail.isis.de>