diff --git a/sysincl.h b/sysincl.h
index 30e9b48..8fe16c0 100644
--- a/sysincl.h
+++ b/sysincl.h
@@ -70,4 +70,8 @@
 #include <arpa/inet.h>
 #endif
 
+#if defined(LINUX) && !defined(IP_FREEBIND)
+#define IP_FREEBIND 15
+#endif
+
 #endif /* GOT_SYSINCL_H */