Add iOS as a Tier 3 platform

[Susurrus]

With this and #639, then we have at least basic testing recurring for all mobile platforms (note that this is more than the libc currently tests, so we may have trouble moving the non-x86 targets to Tier2 until that happens).

[asomers]

ios isn't listed as a supported target at https://github.com/japaric/cross . Is the documentation just out of date? You should try cross building cargo for ios. If it works, then you can update cross's supported target list. If not, then I don't think we can trust cross to build nix for that platform.

Also, the build error looks ominous: error[E0463]: can't find crate for std

[Susurrus]

It isn't listed, but I'm working on the trust side of things in japaric/trust#72.

[Susurrus]

So this now works for building all 5 iOS targets. I don't think this is too controversial, as nobody's chimed in here, so I'll go ahead and merge this in a bit if someone doesn't beat me to it.

[Susurrus]

bors r+

[bors]

Build failed

• continuous-integration/travis-ci/push

[Susurrus]

Was an intermittent failure from one of the errno tests. I think we'll need to create a new subprocess for those tests.

bors r+

[bors]

Build failed

• continuous-integration/travis-ci/push

[Susurrus]

test::sys::test_aio::test_aio_cancel_all() failed this most recent time. The solution might be to run these tests in separate processes or just not run the tests in QEMU.

Let's try this again...

bors r+

[asomers]

@Susurrus I saw that test fail recently for powerpc. Which arch failed it just now?

[Susurrus]

@asomers powerpc-unknown-linux-gnu

[Susurrus]

I've definitely seen it fail before. I'm betting most of those tests need to be disabled on powerpc as well because of weird QEMU issues.

[Susurrus]

LOL, back to test_errno_values not finishing. Have you seen that fail as well?

[asomers]

I haven't seen any problems with test_errno_values

[bors]

Build failed

• continuous-integration/travis-ci/push

[Susurrus]

I'm going to try running tests using a single thread and see if that does anything. I can't imagine why test_errno_values stalls out as it doesn't have any looping and it's a fairly simple test. This is my first attempt to debug it.

[asomers]

I thought it was sufficient to put CARGO_TEST_THREADS=1 in .travis.yml. I guess we'll see.

[Susurrus]

It wouldn't be, because cross gets rid of all environment variables but it allows a whitelist of environment variables.

[Susurrus]

Well that worked, I'm going to move that testing commit to another branch, and we'll see if it works there.

[Susurrus]

And of course, now all the tests pass...

bors r+

[Susurrus]

I guess I could just merge this without relying on bors, since we're a pretty low-traffic repo, but I'll do this the "right" way here.

[bors]

Build succeeded

• continuous-integration/travis-ci/push
• buildbot/nix-rust/nix fbsd11