2976 remove useless offsetof() macros

@@ -39,10 +39,11 @@
 #include <sys/disp.h>
 #include <sys/sdt.h>
 #include <sys/cred.h>
 #include <sys/list.h>
 #include <sys/vscan.h>
+#include <sys/sysmacros.h>
 
 #define VS_REQ_MAGIC            0x52515354 /* 'RQST' */
 
 #define VS_REQS_DEFAULT         20000   /* pending scan requests - reql */
 #define VS_NODES_DEFAULT        128     /* concurrent file scans */

@@ -55,11 +56,10 @@
 #define VS_ACCESS_UNDEFINED     0
 #define VS_ACCESS_ALLOW         1       /* return 0 */
 #define VS_ACCESS_DENY          2       /* return EACCES */
 
 #define tolower(C)      (((C) >= 'A' && (C) <= 'Z') ? (C) - 'A' + 'a' : (C))
-#define offsetof(s, m)  (size_t)(&(((s *)0)->m))
 
 /* global variables - tunable via /etc/system */
 uint32_t vs_reqs_max = VS_REQS_DEFAULT; /* max scan requests */
 uint32_t vs_nodes_max = VS_NODES_DEFAULT; /* max in-progress scan requests */
 uint32_t vs_workers = VS_WORKERS_DEFAULT; /* max workers send reqs to vscand */