Assume that dup3 is available

socket/Makefile

@@ -31,6 +31,6 @@ routines := accept bind connect getpeername getsockname getsockopt	\
 	    setsockopt shutdown socket socketpair isfdtype opensock	\
 	    sockatmark accept4 recvmmsg sendmmsg
 
-aux	 := have_sock_cloexec sa_len
+aux	 := sa_len
 
 include ../Rules

socket/have_sock_cloexec.c

@@ -1,24 +0,0 @@
-/* Copyright (C) 2008-2017 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#include <fcntl.h>
-#include <sys/socket.h>
-#include <kernel-features.h>
-
-#if defined O_CLOEXEC && !defined __ASSUME_DUP3
-int __have_dup3;
-#endif