Add tvOS and watchOS support, identical to iOS support

[thomcc]

This adds tvOS and watchOS support. Support in the Rust stdlib in watchOS is recent, and tvOS is in progress.

These OSes all can use the same interface from Security.framework. Ideally they'd use getrandom, but sadly they currently cannot. I've renamed ios.rs to apple-other.rs as a result of this, but there are no other changes.

[josephlr]

Given that these targets are not super well supported currently, it's fine that we don't run the tests in CI. However, we should do something similar to our build and link tests for Apple Arm64. You should just be able to add the targets to the tests.yml

[thomcc]

Given that these targets are not super well supported currently, it's fine that we don't run the tests in CI. However, we should do something similar to our build and link tests for Apple Arm64. You should just be able to add the targets to the tests.yml

Hm, cargo test --no-run --target=arm64_32-apple-watchos -Zbuild-std --features=std fails with a pretty obscure linker error. I guess we don't pass things to the linker correctly for arm64_32 (I mostly am making this PR for tvOS, but figured I'd add watchOS while I was here).

For tvos it's not currently supported in libstd, so the best we could do is cargo check. I'll follow up here later.

[josephlr]

Hm, cargo test --no-run --target=arm64_32-apple-watchos -Zbuild-std --features=std fails with a pretty obscure linker error. I guess we don't pass things to the linker correctly for arm64_32.

Does this issue occur of the other watchOS targets (i.e. {aarch64,x86_64}-apple-watchos-sim or armv7k-apple-watchos)? We really only need to check one of them in our CI. I would check myself, but I don't have a mac.

If you can get one of them working, add it here.

(I mostly am making this PR for tvOS, but figured I'd add watchOS while I was here).

Makes sense. If linking doesn't work, just add a comment and put the watchOS target with the tvOS target for now.

For tvos it's not currently supported in libstd, so the best we could do is cargo check. I'll follow up here later.

This makes sense, can you add aarch64-apple-tvos to the list of no_std targets here.

[thomcc]

Does this issue occur of the other watchOS targets (i.e. {aarch64,x86_64}-apple-watchos-sim or armv7k-apple-watchos)? We really only need to check one of them in our CI. I would check myself, but I don't have a mac.

Good call, the simulator targets work, which actually helps point out what this issue probably is. Thanks.

Some notes:

• The watchos-sim target is not distributed via rustup, so I had to just -Zbuild-std it. Let me know if you want me to move it elsewhere or something.
• I did have to bump your libc version to 0.2.136 for tvOS, to get Add support for tvOS rust-lang/libc#2958.

[josephlr]

Other than some nits for the CI, this looks reasonable.

Bumping the libc version is fine. For reference rust-lang/libc@bf618c9 is the commit we need.

[thomcc]

Thanks, is this more what you meant?

[thomcc]

Ah, -Zbuild-std requires nightly, do you want me to move it to another job, or would you rather make that one use nightly?

[josephlr]

requires nightly, do you want me to move it to another job, or would you r

Having that one use nightly is fine, ideally it would be in its own job, but macOS runners are slow and constrained on Github Actions, so reducing the jobs generally makes things better.

[thomcc]

I've updated that job to nightly.