diff --git a/lib/prefix.h b/lib/prefix.h
index 45889e0..a1a0679 100644
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -156,6 +156,16 @@
 /* Prefix's family member. */
 #define PREFIX_FAMILY(p)  ((p)->family)
 
+/* glibc defines s6_addr32 to __in6_u.__u6_addr32 if __USE_{MISC || GNU} */
+#ifndef s6_addr32
+#if defined(SUNOS_5)
+/* Some SunOS define s6_addr32 only to kernel */
+#define s6_addr32 _S6_un._S6_u32
+#else
+#define s6_addr32 __u6_addr.__u6_addr32
+#endif /* SUNOS_5 */
+#endif /*s6_addr32*/
+
 /* Prototypes. */
 extern int afi2family (afi_t);
 extern afi_t family2afi (int);
diff --git a/ripngd/ripng_nexthop.h b/ripngd/ripng_nexthop.h
index 7c04105..19bd32b 100644
--- a/ripngd/ripng_nexthop.h
+++ b/ripngd/ripng_nexthop.h
@@ -41,17 +41,8 @@
  * -1 if A < B
  **/
 static inline int
-addr6_cmp(struct in6_addr *A, struct in6_addr *B) {
-
-#ifndef s6_addr32
-#if defined(SUNOS_5)
-/* Some SunOS define s6_addr32 only to kernel */
-#define s6_addr32 _S6_un._S6_u32
-#else
-#define s6_addr32 __u6_addr.__u6_addr32
-#endif /* SUNOS_5 */
-#endif /*s6_addr32*/
-
+addr6_cmp(struct in6_addr *A, struct in6_addr *B)
+{
 #define a(i) A->s6_addr32[i]
 #define b(i) B->s6_addr32[i]