That way this works on musl as well!

Closes #16

Update rand requirement from 0.6.5 to 0.7.0

Updates the requirements on [rand](https://github.com/rust-random/rand) to permit the latest version.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-random/rand/commits

)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Convert RawPthread to libc::pthread_t

Add support for non-unix and non-windows platforms

Cross process jobserver and thread cancellation is not supported

Hopefully useful for rust-lang/cargo#6747

Bump rand

bump tokio-process to 0.2

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>

Shutting down a Unix thread is mega-hard and apparently not very portable. Plus
it's basically racy as we're simply pausing for a bit waiting for a thread to
shut down, but in theory could take awhile.

Observed in https://bugzilla.mozilla.org/show_bug.cgi?id=1445413 it's not really
critical to unconditionally always shut down the helper thread and otherwise
it's generally a bad idea to panic in destructors.

As a result basically just ignore the ability to shut down the helper thread.

Bump rand to 0.4

Validate jobserver fd more conservatively

Handle ENOSYS when calling `pipe2`

Just because libc has the symbol, doesn't mean the kernel supports it.

Based on rust-lang/rust#42521.

This text historically was copied verbatim from rust-lang/rust's own README [1]
with the intention of licensing projects the same as rustc's own license, namely
a dual MIT/Apache-2.0 license. The clause about "various BSD-like licenses"
isn't actually correct for almost all projects other than rust-lang/rust and
the wording around "both" was slightly ambiguous.

This commit updates the wording to match more precisely what's in the
standard library [2], namely clarifying that there aren't any BSD-like licenses
in this repository and that the source is licensable under either license, at
your own discretion.

[1]: https://github.com/rust-lang/rust/tree/f0fe716dbcbf2363ab8f929325d32a17e51039d0#license
[2]: https://github.com/rust-lang/rust/blob/f0fe716dbcbf2363ab8f929325d32a17e51039d0/src/libstd/lib.rs#L5-L9