2976 remove useless offsetof() macros

*** 33,42 ****
--- 33,43 ----
  #include <locale.h>
  #include <string.h>
  #include <ctype.h>
  #include <limits.h>
  #include <errno.h>
+ #include <stddef.h>
  
  #include <pool.h>
  #include "utils.h"
  #include "poolstat.h"
  #include "poolstat_utils.h"
*** 44,55 ****
  
  #ifndef TEXT_DOMAIN
  #define TEXT_DOMAIN     "SYS_TEST"
  #endif
  
- /* calculate offset of a particular element in a structure      */
- #define offsetof(s, m)  ((size_t)(&(((s *)0)->m)))
  #define addrof(s)  ((char **)&(s))
  
  /* verify if a field is printable in respect of the current option flags */
  #define PRINTABLE(i)    ((lf->plf_ffs[(i)].pff_prt & D_FIELD) || \
          (lf->plf_ffs[(i)].pff_prt & X_FIELD))
--- 45,54 ----