Initial support for gambit-scheme v4.7.0

ports/glibc-compat/src/getprotobyname_r.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include <netdb.h>
 
 struct protoent *getprotobyname(const char *name) {
   return NULL;
 }
 
+struct protoent *getprotobynumber(int n) {
+  return NULL;
+}
+
 int __getprotobyname_r(const char *name,
                        struct protoent *result_buf, char *buf,
                        size_t buflen, struct protoent **result)
 {
   *result = NULL;
   return 1;
 }