o Add the pipe implementation to the list of targets to lock. It isn't
mentioned in the list because details aren't, but this is complicated by the presence of VM magic in the pipe implementation. However, VM isn't involved in small pipe operations, and small pipe operations are critical to the performance of large build operations involving make. It looks like pushing small pipe operations out from under giant would have a large impact on build performance, making this an appealing target as file_ops becomes safe.