UWP standard library no longer builds

[jdm]

Code

Running cargo build --target x86_64-uwp-windows-msvc -Z build-std yields:

error[E0432]: unresolved import `SetThreadStackGuarantee`
    --> /home/travis/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/windows/c.rs:1038:12
     |
1038 |     pub fn SetThreadStackGuarantee(_size: *mut c_ulong) -> BOOL {
     |            ^^^^^^^^^^^^^^^^^^^^^^^ use of undeclared type `SetThreadStackGuarantee`
error: aborting due to previous error
error: could not compile `std`

Version it worked on

This works in July 27 rustc nightly.

Version with regression

It's broken in the Oct 6 rustc nightly, but possibly earlier.

[jdm]

It looks like this code is responsible; presumably the compat_fn! macro doesn't handle the attribute correctly.

[jdm]

I suspect 8b2bdfd.

[jdm]

Verified that the 9/30 nightly works.

[camelid]

Assigning P-medium and removing I-prioritize as discussed in the prioritization working group.