2976 remove useless offsetof() macros

@@ -670,13 +670,10 @@
 #define fr_tif          fr_tifs[0]
 #define fr_rif          fr_tifs[1]
 
 #define FR_NOLOGTAG     0
 
-#ifndef offsetof
-#define offsetof(t,m)   (size_t)((&((t *)0)->m))
-#endif
 #define FR_CMPSIZ       (sizeof(struct frentry) - \
                          offsetof(struct frentry, fr_func))
 
 /*
  * fr_type