Added FD_CLOEXEC flag to client/server socket file descriptors

runtime/bin/fdutils.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_FDUTILS_H_
 #define BIN_FDUTILS_H_
 
 #include "bin/builtin.h"
 #include "platform/globals.h"
 
 class FDUtils {
  public:
+  static bool SetCloseOnExec(intptr_t fd);
+
   static bool SetNonBlocking(intptr_t fd);
   static bool SetBlocking(intptr_t fd);
 
   // Checks whether the file descriptor is blocking. If the function
   // returns true the value pointed to by is_blocking will be set to
   // the blocking state of the file descriptor. If the function
   // returns false the system call for checking the file descriptor
   // failed and the value pointed to by is_blocking is not modified.
   static bool IsBlocking(intptr_t fd, bool* is_blocking);
 
@@ skipping 10 matching lines @@
   // which case it returns -1 and errno is still valid. The file
   // descriptor must be in blocking mode.
   static ssize_t WriteToBlocking(int fd, const void* buffer, size_t count);
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(FDUtils);
 };
 
 #endif  // BIN_FDUTILS_H_