Short version for non-lawyers:

os_error is dual-licensed under Apache 2.0 and MIT
terms.


Longer version:

Copyright (c) for portions of os_error are held by The Rust Project
Developers, 2012-2014 as part of The Rust Standard Library.
All other copyright for os_error are held by Simon Wörner, 2018.

Except as otherwise noted in individual files, os_error is
licensed under the Apache License, Version 2.0 <LICENSE-APACHE> or
<http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
<LICENSE-MIT> or <http://opensource.org/licenses/MIT>, at your option.