cygwin std does not build in Miri

[Noratrieb]

https://does-it-build.noratrieb.dev/target?target=x86_64-pc-cygwin

Since 2025-05-19, std does not build for cygwin in Miri.

https://does-it-build.noratrieb.dev/build?nightly=2025-07-05&target=x86_64-pc-cygwin&mode=miri-std looks like some cfgs are messed up in the stack_overflow module.

[Noratrieb]

@Berrysoft

[Berrysoft]

Miri never built, actually. Even if you fix the std here, it doesn't run correctly because of lacking pthread syscalls support.

[Noratrieb]

Ah I see, I forgot what Miri specific things exist in std :).

[ChrisDenton]

This just needs a not(miri)

rust/library/std/src/sys/pal/unix/stack_overflow.rs

Line 644 in f0b67dd

#[cfg(target_os = "cygwin")]

[Berrysoft]

Yes. I didn't fix it because anyway Miri doesn't work... and it won't affect other platforms.