--- /dev/null
+diff --git a/noip.c b/noip.c
+index aca7b75..479bdf5 100644
+--- a/noip.c
++++ b/noip.c
+@@ -57,6 +57,11 @@
+ #include <ifaddrs.h>
+ #include <netdb.h>
+
++#ifndef SUN_LEN
++# define SUN_LEN(sun) \
++ (strlen((sun)->sun_path) + offsetof(struct sockaddr_un, sun_path))
++#endif
++
+ /*----- Data structures ---------------------------------------------------*/
+
+ /* Unix socket status values. */
+diff --git a/uopen.c b/uopen.c
+index 3c0d1d4..22b09db 100644
+--- a/uopen.c
++++ b/uopen.c
+@@ -42,6 +42,11 @@
+ #include <sys/stat.h>
+ #include <sys/un.h>
+
++#ifndef SUN_LEN
++# define SUN_LEN(sun) \
++ (strlen((sun)->sun_path) + offsetof(struct sockaddr_un, sun_path))
++#endif
++
+ /*----- Import the real versions of functions -----------------------------*/
+
+ /* The list of functions to immport. */