* include/std/condition_variable (condition_variable_any::_Unlock): Do
	not swallow __forced_unwind.
	* include/std/future (__future_base::_Task_setter): Likewise.
	(__future_base::_Async_state_impl): Turn __forced_unwind into broken
	promise and rethrow.
	* include/std/mutex (try_lock): Likewise.
	* testsuite/30_threads/async/forced_unwind.cc: New.
	* testsuite/30_threads/packaged_task/forced_unwind.cc: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@211138 138bc75d-0d04-0410-961f-82ee72b054a4