make windows compat_fn (crudely) work on Miri
With https://github.com/rust-lang/rust/pull/95469, Windows `compat_fn!` now has to be supported by Miri to even make stdout work. Unfortunately, it relies on some outside-of-Rust linker hacks (`#[link_section = ".CRT$XCU"]`) that are rather hard to make work in Miri. So I came up with this crude hack to make this stuff work in Miri regardless. It should come at no cost for regular executions, so I hope this is okay.
Cc https://github.com/rust-lang/rust/issues/95627 `@ChrisDenton`
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