externals: Update boost to 1.72 and add Boost Context

boost/thread/is_locked_by_this_thread.hpp

@@ -0,0 +1,39 @@
+// (C) Copyright 2012 Vicente J. Botet Escriba
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+
+#ifndef BOOST_THREAD_IS_LOCKED_BY_THIS_THREAD_HPP
+#define BOOST_THREAD_IS_LOCKED_BY_THIS_THREAD_HPP
+
+#include <boost/thread/detail/config.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+namespace boost
+{
+  template <typename Lockable>
+  class testable_mutex;
+
+  /**
+   * Overloaded function used to check if the mutex is locked when it is testable and do nothing otherwise.
+   *
+   * This function is used usually to assert the pre-condition when the function can only be called when the mutex
+   * must be locked by the current thread.
+   */
+  template <typename Lockable>
+  bool is_locked_by_this_thread(testable_mutex<Lockable> const& mtx)
+  {
+    return mtx.is_locked_by_this_thread();
+  }
+  template <typename Lockable>
+  bool is_locked_by_this_thread(Lockable const&)
+  {
+    return true;
+  }
+}
+
+#include <boost/config/abi_suffix.hpp>
+
+#endif // header