diff -urN fetchmail-5.6.6.org/ipv6-connect.c fetchmail-5.6.6/ipv6-connect.c
--- fetchmail-5.6.6.org/ipv6-connect.c	Mon Feb 19 20:30:59 2001
+++ fetchmail-5.6.6/ipv6-connect.c	Mon Feb 19 20:33:09 2001
@@ -21,7 +21,11 @@
 #include <signal.h>
 
 #ifndef SA_LEN
-#define SA_LEN(sa)	((sa)->sa_len)
+#ifdef __GLIBC__
+#define SA_LEN(sa)	((sa)->sa_family == AF_INET6 ? sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in))
+#else
+#define	SA_LEN(sa)	((sa)->sa_len)
+#endif
 #endif
 
 #ifdef INET6_ENABLE