3373 gcc >= 4.5 concerns about offsetof()

*** 34,44 ****
  #include <sys/nsctl/dsw.h>
  #include <sys/nsctl/dsw_dev.h>
  
  #include <sys/nsctl/nsvers.h>
  
! #define offsetof(s, m)  ((size_t)(&((s *)0)->m))
  
  
  const mdb_bitmask_t bi_flags_bits[] = {
          { "DSW_GOLDEN", DSW_GOLDEN, DSW_GOLDEN },
          { "DSW_COPYINGP", DSW_COPYINGP, DSW_COPYINGP },
--- 34,48 ----
  #include <sys/nsctl/dsw.h>
  #include <sys/nsctl/dsw_dev.h>
  
  #include <sys/nsctl/nsvers.h>
  
! #if defined(__GNUC__)
! #define offsetof(s, m)  __builtin_offsetof(s, m)
! #else
! #define offsetof(s, m)  ((size_t)(&(((s *)0)->m)))
! #endif
  
  
  const mdb_bitmask_t bi_flags_bits[] = {
          { "DSW_GOLDEN", DSW_GOLDEN, DSW_GOLDEN },
          { "DSW_COPYINGP", DSW_COPYINGP, DSW_COPYINGP },