Add working realpath implementation to glibc-compat

ports/glibc-compat/src/stubs.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 <arpa/inet.h>
 #include <errno.h>
 #include <grp.h>
 #include <pwd.h>
@@ skipping 422 matching lines @@
   UNIMPLEMENTED_FATAL();
 }
 
 int connect(int sockfd, const struct sockaddr *addr,
             socklen_t addrlen) __attribute__ ((weak));
 int connect(int sockfd, const struct sockaddr *addr,
                    socklen_t addrlen) {
   UNIMPLEMENTED_FATAL();
 }
 
-char* realpath(const char* path, char* resolved) __attribute__ ((weak));
-char* realpath(const char* path, char* resolved) {
-  UNIMPLEMENTED_NOSYS_RTN(NULL);
-}
-
 int getaddrinfo(const char *, const char *, const struct addrinfo *,
                 struct addrinfo **) __attribute__ ((weak));
 int getaddrinfo(const char *node, const char *service,
                 const struct addrinfo *hints, struct addrinfo **res) {
   errno = ENOSYS;
   UNIMPLEMENTED_NOSYS_RTN(EAI_SYSTEM);
 }
 
 void freeaddrinfo(struct addrinfo *) __attribute__ ((weak));
 void freeaddrinfo(struct addrinfo *res) {
@@ skipping 18 matching lines @@
 
 int mknod(const char *pathname, mode_t mode, dev_t dev) __attribute__ ((weak));
 int mknod(const char *pathname, mode_t mode, dev_t dev) {
   UNIMPLEMENTED_NOSYS();
 }
 
 int mkfifo(const char *pathname, mode_t mode) __attribute__ ((weak));
 int mkfifo(const char *pathname, mode_t mode) {
   UNIMPLEMENTED_NOSYS();
 }