2976 remove useless offsetof() macros

@@ -27,10 +27,11 @@
 #include <sys/ksynch.h>
 #include <sys/cmn_err.h>
 #include <sys/kmem.h>
 #include <sys/conf.h>
 #include <sys/errno.h>
+#include <sys/sysmacros.h>
 
 #ifdef _SunOS_5_6
 /*
  * on 2.6 both dki_lock.h and rpc/types.h define bool_t so we
  * define enum_t here as it is all we need from rpc/types.h

@@ -5637,17 +5638,10 @@
         mutex_exit(&rdc_conf_lock);
 
         return (rc);
 }
 
-/*
- * Yet another standard thing that is not standard ...
- */
-#ifndef offsetof
-#define offsetof(s, m)  ((size_t)(&((s *)0)->m))
-#endif
-
 static int
 rdc_status(void *arg, int mode, rdc_config_t *uparms, spcs_s_info_t kstatus)
 {
         rdc_k_info_t *krdc;
         rdc_u_info_t *urdc;