for MacOS, define unknown symbols to equivalent values

sslh-fork.c

@@ -164,6 +164,17 @@ void set_listen_procname(struct listen_endpoint *listen_socket)
 }
 
 
+/* At least MacOS does not know these two options, so define them to something
+ * equivalent for our use case */
+#ifndef ENONET
+#define ENONET ENETDOWN
+#endif
+
+#ifndef EOPNOTSUPP
+#define EOPNOTSUPP ENETDOWN
+#endif
+/* /MacOS kludge */
+
 /* TCP listener: connections, fork a child for each new connection 
  * IN: 
  *      endpoint: array of listening endpoint objects