Handle failure conditions correctly in pipes.

src/rt/rust_builtin.cpp

@@ -930,11 +930,11 @@ task_clear_event_reject(rust_task *task) {
 // Waits on an event, returning the pointer to the event that unblocked this
 // task.
 extern "C" void *
-task_wait_event(rust_task *task) {
+task_wait_event(rust_task *task, bool *killed) {
     // TODO: we should assert that the passed in task is the currently running
     // task. We wouldn't want to wait some other task.
 
-    return task->wait_event();
+    return task->wait_event(killed);
 }
 
 extern "C" void