Index: src/assuan-socket.c
===================================================================
--- src/assuan-socket.c
+++ src/assuan-socket.c
@@ -35,6 +35,9 @@
 # include <sys/types.h>
 # include <sys/socket.h>
 # include <netinet/in.h>
+#if __MAC_OS_X_VERSION_MIN_REQUIRED < 1050 /* or 1060, when Leopard, Mac OS X 10.6, needs it also */
+  #define	INADDR_LOOPBACK		(u_int32_t)0x7f000001
+#endif   /* __MAC_OS_X_VERSION_MIN_REQUIRED < 1050 */
 # include <arpa/inet.h>
 #endif
 #include <errno.h>