atomics: always #include <stdbool.h>

so the bool type is defined when using old compilers that do not support gcc builtin atomics (such as gcc 4.1.x from CentOS 5)

Fixes open-mpi/ompi#4478

Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>

opal/include/opal/sys/atomic.h

@@ -53,6 +53,8 @@
 
 #include "opal_config.h"
 
+#include <stdbool.h>
+
 #include "opal/sys/architecture.h"
 #include "opal_stdint.h"
 

opal/include/opal/sys/gcc_builtin/atomic.h

@@ -13,7 +13,7 @@
  * Copyright (c) 2011      Sandia National Laboratories. All rights reserved.
  * Copyright (c) 2014-2017 Los Alamos National Security, LLC. All rights
  *                         reserved.
- * Copyright (c) 2016      Research Organization for Information Science
+ * Copyright (c) 2016-2017 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * $COPYRIGHT$
  *
@@ -25,8 +25,6 @@
 #ifndef OPAL_SYS_ARCH_ATOMIC_H
 #define OPAL_SYS_ARCH_ATOMIC_H 1
 
-#include <stdbool.h>
-
 /**********************************************************************
  *
  * Memory Barriers