diff --git a/contrib/MacOSX/config.h b/contrib/MacOSX/config.h
index 86b460b1..5b47e9da 100644
--- a/contrib/MacOSX/config.h
+++ b/contrib/MacOSX/config.h
@@ -74,6 +74,8 @@
 /* Define to 1 if you have the <netinet/ip.h> header file. */
 #define HAVE_NETINET_IP_H 1
 
+/* Define to 1 if you have the `gai_strerror' function. */
+#define HAVE_GAI_STRERROR 1
 /* Define to 1 if you have the `kqueue' function. */
 #define HAVE_KQUEUE 1
 /* Define to 1 if you have the `inet_ntoa' function. */