Prevent GCC 6 <cstdlib> from including /usr/include/stdlib.h

quick_exit tests: Do not use C++ headers

If C++ headers such as <cstdlib> or <thread> are used, GCC 6
will include /usr/include/stdlib.h (instead of stdlib/stdlib.h
in the glibc source directory), and this turns up as a make
dependency.  An implicit rule will kick in and make will try to
install stdlib/stdlib.h as /usr/include/stdlib.h because the
target is out of date.

This commit switches to <stdlib.h> and <pthread.h> instead of
<cstdlib> and <thread>.

2016-06-09  Florian Weimer  <fweimer@redhat.com>

	Prevent GCC 6 <cstdlib> from including /usr/include/stdlib.h.
	* stdlib/tst-quick_exit.cc: Include <stdlib.h> instead of
	<cstdlib>.
	(optimization_barrier): New.
	(do_test): Use it.  Call quick_exit in the global namespace.
	* stdlib/tst-thread-quick_exit.cc: Include <stdlib.h>, <pthread.h>
	instead of <cstdlib>, <thread>.
	(optimization_barrier): New.
	(non_main_thread): Adjust declaration.  Call optimization_barrier.
	Call quick_exit in the global namespace.
	(do_test): Call optimization_barrier.  Use pthread_create,
	pthread_join instead of std::thread.

diff --git a/stdlib/tst-quick_exit.cc b/stdlib/tst-quick_exit.cc
index c4a15a9..6fb99c4 100644
--- a/stdlib/tst-quick_exit.cc
+++ b/stdlib/tst-quick_exit.cc
@@ -15,24 +15,31 @@ 
    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 <cstdlib>
+
+#include <stdlib.h>
 
 struct A
 {
-  ~A() { abort(); }
+  ~A () { abort (); }
 };
 
 thread_local A a;
 
+void
+__attribute__ ((noinline, noclone))
+optimization_barrier (A &)
+{
+}
+
 static int
-do_test()
+do_test ()
 {
-  (void)a;
+  optimization_barrier (a);
   /* The C++11 standard in 18.5.12 says:
      "Objects shall not be destroyed as a result of calling
       quick_exit."
      If quick_exit calls the destructors the test aborts.  */
-  std::quick_exit(0);
+  quick_exit (0);
   return 0;
 }
 
diff --git a/stdlib/tst-thread-quick_exit.cc b/stdlib/tst-thread-quick_exit.cc
index 307d2a2..057cc04 100644
--- a/stdlib/tst-thread-quick_exit.cc
+++ b/stdlib/tst-thread-quick_exit.cc
@@ -15,35 +15,51 @@ 
    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 <cstdlib>
-#include <thread>
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
 
 struct A
 {
-  ~A() { abort(); }
+  ~A () { abort (); }
 };
 
 thread_local A a1;
 thread_local A a2;
 
+void
+__attribute__ ((noinline, noclone))
+optimization_barrier (A &)
+{
+}
+
 /* Call std::quick_exit from a non-main thread.  */
-void non_main_thread (void)
+void *
+non_main_thread (void *)
 {
-  (void)a1;
+  optimization_barrier (a1);
   /* The C++11 standard in 18.5.12 says:
      "Objects shall not be destroyed as a result of calling
       quick_exit."
      If quick_exit calls the destructors the test aborts.  */
-  std::quick_exit (0);
+  quick_exit (0);
 }
 
 static int
 do_test()
 {
-  (void)a2;
-  std::thread th (non_main_thread);
-  th.join ();
-  return 0;
+  optimization_barrier (a2);
+  pthread_t thr;
+  int ret = pthread_create (&thr, NULL, non_main_thread, NULL);
+  if (ret != 0)
+    {
+      errno = ret;
+      printf ("error: pthread_create: %m\n");
+    }
+  pthread_join (thr, NULL);
+  return 1;
 }
 
 #define TEST_FUNCTION do_test ()