Better iOS support

[vhbit]

Includes fixes to ABI and also now supports almost all targets available for iOS platform: armv7, armv7s, aarch64 (arm64) for devices and i386, x86_64 for simulator. So the only missing for now are thumbv7 and thumbv7s.

[rust-highfive]

r? @alexcrichton

(rust_highfive has picked a reviewer for you, use r? to override)

[vhbit]

It actually will pass all buildbots at is, but for actual compilation for aarch64 it requires rust-lang/compiler-rt#8 to land.

[vhbit]

@alexcrichton any chance to get it into alpha?

[vhbit]

Rebased after target_word_size -> target_pointer_width

[tomjakubowski]

Need another rebase

[vhbit]

@tomjakubowski can you elaborate? I've built with those changes after rollup

[vhbit]

@tomjakubowski disregard prev message, fixed.

[tomjakubowski]

At the time I commented there was a fresh merge conflict warning on the PR (and I didn't see recently pushed commits), I guess GitHub was just a bit out of sync!

[alexcrichton]

You may want to also assert that the process exited with a 0 exit code as it may help debug when things go wrong.

[alexcrichton]

Looks great, thanks @vhbit for the continued support here!

Now that I've merged rust-lang/compiler-rt#8, do you want to throw that in as well?

[vhbit]

@alexcrichton addressed nits in new commits, will squash them later (and delete cabi_arm_ios.rs) if there is nothing more.

[alexcrichton]

Ah I see now, looks good to me @vhbit! There's also a tidy error you may be interested in.

[vhbit]

@alexcrichton tidy error is about URL to Apple docs, what is a preffered way to fix this (leave/split/use shortener)?

[alexcrichton]

I'd be fine just splitting:

// http://example.com/really/long
//                   /url

[vhbit]

@alexcrichton squashed with prev commits and cleaned up a bit

[vhbit]

Nah, one more tidy issue :(

[vhbit]

Fixed (hope it's the last thing)