+ /* In the w32 Emacs port, fcntl (fd, F_DUPFD_CLOEXEC, fd1) is always
+ invoked in a context where fd1 is closed and all descriptors less
+ than fd1 are open, so sys_dup is an adequate implementation. */
+ if (cmd == F_DUPFD_CLOEXEC)
+ return sys_dup (s);
+