Change this offsetof computation to use c89 offsetof. Tested:

diff --git a/socket/sys/un.h b/socket/sys/un.h
index 332ba0ecc79dbd6b4f1440385f07dfa3798bbf9c..8a3a9c7016c9a92badb250a0dca6f1b024f6c92e 100644 (file)
--- a/socket/sys/un.h
+++ b/socket/sys/un.h
@@ -40,7 +40,7 @@ struct sockaddr_un
 
 #ifdef __USE_MISC
 /* Evaluate to actual length of the `sockaddr_un' structure.  */
-# define SUN_LEN(ptr) ((size_t) (((struct sockaddr_un *) 0)->sun_path)       \
+# define SUN_LEN(ptr) (offsetof(struct sockaddr_un, sun_path)                 \
                      + strlen ((ptr)->sun_path))
 #endif