fd_set 관련 컴파일 문제 도움 요청드립니다.

#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/signal.h>
#include <sys/un.h>
#include <unistd.h>
#include <strings.h>
#include <string.h>
 
int wait_reply(fd, time_out)
int    fd;
int    time_out;
{
    struct    timeval    t_val;
    struct    fd_set    fdset;
    int    irv;
 
    t_val.tv_sec  = time_out;
    t_val.tv_usec = 0;        /* microtime 무시        */
 
    FD_ZERO(&fdset);
    FD_SET(fd, &fdset);
 
    if (time_out < 0)
    {
        irv = select(fd+1, &fdset, NULL, NULL, NULL);
    }
    else
    {
        errno = 0;
        irv = select(fd+1, &fdset, NULL, NULL, &t_val);
    }
    return (irv);
}

wrk_data_comm_lb.c: In function ‘wait_reply’:
wrk_data_comm_lb.c:5148:25: error: storage size of ‘fdset’ isn’t known
     struct    fd_set    fdset;
                         ^
make[1]: *** [wrk_data_comm_lb.o] 오류 1

-- types.h --
 
/* It also defines `fd_set' and the FD_* macros for `select'.  */
# include <sys/select.h>
 
-- select.h --
 
/* fd_set for select and pselect.  */
typedef struct
  {
    /* XPG4.2 requires this member name.  Otherwise avoid the name
       from the global namespace.  */
#ifdef __USE_XOPEN
    __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS];
# define __FDS_BITS(set) ((set)->fds_bits)
#else
    __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
# define __FDS_BITS(set) ((set)->__fds_bits)
#endif
  } fd_set;