This updates the Fuchsia commit used in `auto - x86_64-gnu-integration`
CI bot to use the Rust commit 703dc9c.
This should help improve the coverage of this builder.

It also updates the SDK version to F20.20240412.3.1, and the Fuchsia Clang
version to c777c011a709dffd4fa5e79cad7947b7c3405d02.

Add a test that fails if `#[unix_sigpipe = "inherit"]` wrongly results
in `SIGPIPE` being `SIG_DFL` if the parent has `SIG_IGN`. We have no
current test for this particular case.

…r=fmease

Test `#[unix_sigpipe = "inherit"]` with both `SIG_DFL` and `SIG_IGN`

Extend our `#[unix_sigpipe = "inherit"]` test so that it detects if  `SIGPIPE` wrongly ends up being `SIG_DFL` when the parent has `SIG_IGN`. We have no current test for this particular case.

Tracking issue: rust-lang#97889

More DefineOpaqueTypes::Yes

This accepts more code on stable. It is now possible to have match arms return a function item `foo::<ConcreteType>` and a function item `foo::<OpaqueTypeInDefiningScope>` in another, and that will constrain `OpaqueTypeInDefiningScope` to have the hidden type `ConcreteType`. So the following function will now compile, but on master it errors with a type mismatch on the second match arm

```rust
// The function item whose generic params we want to merge.
fn foo<T>(t: T) -> T { t }
// Helper ensuring we can constrain `T` on `F` without explicitly specifying it
fn bind<T, F: FnOnce(T) -> T>(_: T, f: F) -> F { f }

fn k() -> impl Sized {
    let x = match true {
        true => {
            // `f` is `FnDef(foo, [infer_var])`
            let f = foo;
            // Get a value of an opaque type on stable
            let t = k();
            // this returns `FnDef(foo, [k::return])`
            bind(t, f)
        }
        false => foo::<()>,
    };
    todo!()
}
```

r? ``@compiler-errors``

cc rust-lang#116652

Bump Fuchsia versions

This updates the Fuchsia commit used in `auto - x86_64-gnu-integration` CI bot to use the Rust commit 703dc9c. This should help improve the coverage of this builder.

It also updates the SDK version to F20.20240412.3.1, and the Fuchsia Clang version to c777c011a709dffd4fa5e79cad7947b7c3405d02.

r? ``@tmandry``

fix weak memory bug in TLS on Windows

We need to store the `key` *after* we register the dtor.

Now I hope there isn't also some other reason why we have to actually register the dtor last... `@joboet` is there a reason you picked this particular order in rust-lang#102655?

Fixes rust-lang#123583

…nton

windows fill_utf16_buf: explain the expected return value

The comment just says "return what the syscall returns", but that doesn't work for all syscalls as the Windows API is not consistent in how buffer size is negotiated. For instance, GetUserProfileDirectoryW works a bit differently, and so home_dir_crt has to translate this to the usual protocol itself. So it's worth describing that protocol.

r? ``@ChrisDenton``

… r=compiler-errors

Add diagnostic item for `std::iter::Enumerate`

This adds a diagnostic item for `std::iter::Enumerate`.  The change will be used by the clippy `unused_enumerate_index` lint to move away from type paths to using diagnostic items.

see: rust-lang/rust-clippy#5393