Added tcsetpgrp

[tinywombat765]

I added the missing tcsetpgrp function

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @alexcrichton (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[alexcrichton]

@bors: r+

Thanks!

[bors]

📌 Commit c21a30c has been approved by alexcrichton

[bors]

⌛ Testing commit c21a30c with merge 737aca2...

[bors]

💥 Test timed out

[tinywombat765]

What when wrong?

[alexcrichton]

Our automation isn't always working... Looks like CI passed though so I'll merge!