Add watchOS support to sysctl crate

[setoelkahfi]

Transitive dependency when working on adding watchOS support here.

[johalun]

Please rebase and eliminate whitespace changes

[setoelkahfi]

Please rebase and eliminate whitespace changes

@johalun Done

[johalun]

Did you inspect the diff at all? You're changing crate version.

[setoelkahfi]

My bad

[setoelkahfi]

@johalun I need to build my sdk now and my gemm-common transitive dep needs the 0.6 version. Feel free to revert it before merging this, unless you have other concerns.

[johalun]

Since you're working with Apple devices maybe you know, is it safe to assume that all Apple devices have the same sysctl interface and functionality? I'm thinking maybe I'll group them all into a single feature flag is_apple or similar.

[asomers]

Since you're working with Apple devices maybe you know, is it safe to assume that all Apple devices have the same sysctl interface and functionality? I'm thinking maybe I'll group them all into a single feature flag is_apple or similar.

Might I suggest that rather than add a feature flag, you use a cfg target alias? For example: https://github.com/nix-rust/nix/blob/69c05059fb38a85facd63af80456705ad91e9491/build.rs#L21 .

[setoelkahfi]

Since you're working with Apple devices maybe you know, is it safe to assume that all Apple devices have the same sysctl interface and functionality? I'm thinking maybe I'll group them all into a single feature flag is_apple or similar.

Yeah, I believe so. It's Darwin anyway.

The cfg target alias looks neater I would say.

[setoelkahfi]

Hey @johalun, I've rebased and cleaned up the whitespace as requested. I also fixed the version to stay at 0.6.0 since this is a patch on the current release, not a new minor.

Regarding the is_apple cfg alias, I agree with @asomers that a build.rs target alias is the cleanest approach. Happy to implement that in a follow-up PR so we can keep this one minimal (just adding target_os = "watchos" to the existing gates). That way:

1. This PR is small, reviewable, and unblocks watchOS users now (maybe just me)
2. A follow-up PR introduces the cfg(apple) alias and replaces all the any(macos, ios, tvos, visionos, watchos, ...) lists across the codebase, a much cleaner refactor on its own

Let me know if you'd prefer both in one PR or if splitting them works for you.

[setoelkahfi]

@johalun I need to build my sdk now and my gemm-common transitive dep needs the 0.6 version. Feel free to revert it before merging this, unless you have other concerns.