[hurd,commited] htl: Add missing fork.h

[Samuel Thibault]

2b47727c68b6 ("posix: Consolidate register-atfork") introduced a fork.h
header to declare the atfork unregister hook, but was missing adding it
for htl.

This fixes tst-atfork2.
---
 sysdeps/htl/fork.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 sysdeps/htl/fork.h

diff --git a/sysdeps/htl/fork.h b/sysdeps/htl/fork.h
new file mode 100644
index 0000000000..9d0d1d2b41
--- /dev/null
+++ b/sysdeps/htl/fork.h
@@ -0,0 +1,20 @@
+/* Copyright (C) 2002-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <lowlevellock.h>
+#include <register-atfork.h>
-- 
2.30.2