htl: Enable more tests

* nptl/tst-_res1.c, tst-_res1mod1.c, tst-_res1mod2.c, tst-atfork2.c,
tst-atfork2mod.c, tst-fini1.c, tst-fini1mod.c, tst-tls4.c, tst-tls4moda.c,
tst-tls4modb.c: Move to...
* sysdeps/pthread: ... here.  Rename tst-tls4.c to tst-pt-tls4.c to avoid
conflicting with elf/tst-tls4.c.
* nptl/Makefile: Move corresponding references and rules to...
* sysdeps/pthread/Makefile: ... here.

sysdeps/pthread/tst-atfork2mod.c

@@ -0,0 +1,57 @@
+/* Copyright (C) 2003-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+   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 <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <dso_handle.h>
+
+
+extern int val;
+
+
+static void
+prepare (void)
+{
+  ++val;
+}
+
+static void
+parent (void)
+{
+  val *= 4;
+}
+
+static void
+child (void)
+{
+  val *= 8;
+}
+
+static void
+__attribute__ ((constructor))
+init (void)
+{
+  printf ("dsohandle = %p\n", __dso_handle);
+
+  if (pthread_atfork (prepare, parent, child) != 0)
+    {
+      puts ("init: atfork failed");
+      exit (1);
+    }
+}