fix(personality): Fix types for personality constants

[woodruffw]

First of all, thanks for these bindings!

I noticed this while working on some higher-level (nix) bindings for personality(2): these constants are passed to personality(2), which takes a c_ulong. Thus, these should also be c_ulongs, rather than c_int.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @JohnTitor (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 Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed.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.

Please see the contribution instructions for more information.

[JohnTitor]

You're right, sorry for the trouble!
I'd follow this but it's a breaking change, let's make some period before changing actually:

1. Add a deprecation notice like #[deprecated(note = "This type is defined as c_int by mistake. We will change it to c_ulong in the future release")] so that the users know it.
2. After some releases, change the type.

But if we'd consider this as bugfix, we could accept it as-is.

cc @nbaksalyar as you introduced these consts.

[woodruffw]

No worries! On closer inspection, it might actually be reasonable: personality(2) takes a c_ulong but returns a c_int. Moreover the return value of personality(2) (when it isn't an error) is specified to be the previous persona, meaning that all personality values need to fit into c_int and that it's an equally valid type choice.

I'm interested in hearing what @nbaksalyar thinks, but I'd personally be okay with the current signatures in light of the above 🙂

[woodruffw]

I'm gonna go ahead and close this, since I've convinced myself that the current types are correct.