…s, r=workingjubilee

forbid toggling x87 and fpregs on hard-float targets

Part of rust-lang#116344, follow-up to rust-lang#129884:

The `x87`  target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](rust-lang#130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).

Also fixes rust-lang#132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.

The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.

r? `@workingjubilee`

…ingjubilee

forbid toggling x87 and fpregs on hard-float targets

Part of rust-lang/rust#116344, follow-up to rust-lang/rust#129884:

The `x87`  target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](rust-lang/rust#130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).

Also fixes rust-lang/rust#132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.

The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.

r? `@workingjubilee`

…ingjubilee

forbid toggling x87 and fpregs on hard-float targets

Part of rust-lang/rust#116344, follow-up to rust-lang/rust#129884:

The `x87`  target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](rust-lang/rust#130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).

Also fixes rust-lang/rust#132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.

The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.

r? `@workingjubilee`

…ingjubilee

forbid toggling x87 and fpregs on hard-float targets

Part of rust-lang/rust#116344, follow-up to rust-lang/rust#129884:

The `x87`  target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](rust-lang/rust#130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).

Also fixes rust-lang/rust#132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.

The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.

r? `@workingjubilee`

…r=workingjubilee

mark some target features as 'forbidden' so they cannot be (un)set with -Ctarget-feature

The context for this is rust-lang#116344: some target features change the way floats are passed between functions. Changing those target features is unsound as code compiled for the same target may now use different ABIs.

So this introduces a new concept of "forbidden" target features (on top of the existing "stable " and "unstable" categories), and makes it a hard error to (un)set such a target feature. For now, the x86 and ARM feature `soft-float` is on that list. We'll have to make some effort to collect more relevant features, and similar features from other targets, but that can happen after the basic infrastructure for this landed. (These features are being collected in rust-lang#131799.)

I've made this a warning for now to give people some time to speak up if this would break something.

MCP: rust-lang/compiler-team#780

This MR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [rust](https://github.com/rust-lang/rust) | minor | `1.83.0` -> `1.84.0` |

MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot).

**Proposed changes to behavior should be submitted there as MRs.**

---

### Release Notes

<details>
<summary>rust-lang/rust (rust)</summary>

### [`v1.84.0`](https://github.com/rust-lang/rust/blob/HEAD/RELEASES.md#Version-1840-2025-01-09)

[Compare Source](rust-lang/rust@1.83.0...1.84.0)

\==========================

<a id="
Language"></a>

## Language

-   [Allow `#[deny]` inside `#[forbid]` as a no-op](rust-lang/rust#121560)
-   [Show a warning when `-Ctarget-feature` is used to toggle features that can lead to unsoundness due to ABI mismatches](rust-lang/rust#129884)
-   [Use the next-generation trait solver in coherence](rust-lang/rust#130654)
-   [Allow coercions to drop the principal of trait objects](rust-lang/rust#131857)
-   [Support `/` as the path separator for `include!()` in all cases on Windows](rust-lang/rust#125205)
-   [Taking a raw ref (`raw (const|mut)`) of a deref of a pointer (`*ptr`) is now safe](rust-lang/rust#129248)
-   [Stabilize s390x inline assembly](rust-lang/rust#131258)
-   [Stabilize Arm64EC inline assembly](rust-lang/rust#131781)
-   [Lint against creating pointers to immediately dropped temporaries](rust-lang/rust#128985)
-   [Execute drop glue when unwinding in an `extern "C"` function](rust-lang/rust#129582)

<a id="1.84.0-Compiler"></a>

## Compiler

-   [Add `--print host-tuple` flag to print the host target tuple and affirm the "target tuple" terminology over "target triple"](rust-lang/rust#125579)
-   [Declaring functions with a calling convention not supported on the current target now triggers a hard error](rust-lang/rust#129935)
-   [Set up indirect access to external data for `loongarch64-unknown-linux-{musl,ohos}`](rust-lang/rust#131583)
-   [Enable XRay instrumentation for LoongArch Linux targets](rust-lang/rust#131818)
-   [Extend the `unexpected_cfgs` lint to also warn in external macros](rust-lang/rust#132577)
-   [Stabilize WebAssembly `multivalue`, `reference-types`, and `tail-call` target features](rust-lang/rust#131080)
-   [Added Tier 2 support for the `wasm32v1-none` target](rust-lang/rust#131487)

<a id="1.84.0-Libraries"></a>

## Libraries

-   [Implement `From<&mut {slice}>` for `Box/Rc/Arc<{slice}>`](rust-lang/rust#129329)
-   [Move `<float>::copysign`, `<float>::abs`, `<float>::signum` to `core`](rust-lang/rust#131304)
-   [Add `LowerExp` and `UpperExp` implementations to `NonZero`](rust-lang/rust#131377)
-   [Implement `FromStr` for `CString` and `TryFrom<CString>` for `String`](rust-lang/rust#130608)
-   [`std::os::darwin` has been made public](rust-lang/rust#123723)

<a id="1.84.0-Stabilized-APIs"></a>

## Stabilized APIs

-   [`Ipv6Addr::is_unique_local`](https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.is_unique_local)
-   [`Ipv6Addr::is_unicast_link_local`](https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.is_unicast_link_local)
-   [`core::ptr::with_exposed_provenance`](https://doc.rust-lang.org/stable/core/ptr/fn.with_exposed_provenance.html)
-   [`core::ptr::with_exposed_provenance_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.with_exposed_provenance_mut.html)
-   [`<ptr>::addr`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.addr)
-   [`<ptr>::expose_provenance`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.expose_provenance)
-   [`<ptr>::with_addr`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.with_addr)
-   [`<ptr>::map_addr`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.map_addr)
-   [`<int>::isqrt`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.isqrt)
-   [`<int>::checked_isqrt`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.checked_isqrt)
-   [`<uint>::isqrt`](https://doc.rust-lang.org/stable/core/primitive.u32.html#method.isqrt)
-   [`NonZero::isqrt`](https://doc.rust-lang.org/stable/core/num/struct.NonZero.html#impl-NonZero%3Cu128%3E/method.isqrt)
-   [`core::ptr::without_provenance`](https://doc.rust-lang.org/stable/core/ptr/fn.without_provenance.html)
-   [`core::ptr::without_provenance_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.without_provenance_mut.html)
-   [`core::ptr::dangling`](https://doc.rust-lang.org/stable/core/ptr/fn.dangling.html)
-   [`core::ptr::dangling_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.dangling_mut.html)
-   [`Pin::as_deref_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.as_deref_mut)

These APIs are now stable in const contexts

-   [`AtomicBool::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.from_ptr)
-   [`AtomicPtr::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicPtr.html#method.from_ptr)
-   [`AtomicU8::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU8.html#method.from_ptr)
-   [`AtomicU16::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU16.html#method.from_ptr)
-   [`AtomicU32::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU32.html#method.from_ptr)
-   [`AtomicU64::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU64.html#method.from_ptr)
-   [`AtomicUsize::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.from_ptr)
-   [`AtomicI8::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI8.html#method.from_ptr)
-   [`AtomicI16::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI16.html#method.from_ptr)
-   [`AtomicI32::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI32.html#method.from_ptr)
-   [`AtomicI64::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI64.html#method.from_ptr)
-   [`AtomicIsize::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicIsize.html#method.from_ptr)
-   [`<ptr>::is_null`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_null-1)
-   [`<ptr>::as_ref`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.as_ref-1)
-   [`<ptr>::as_mut`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.as_mut)
-   [`Pin::new`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.new)
-   [`Pin::new_unchecked`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.new_unchecked)
-   [`Pin::get_ref`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_ref)
-   [`Pin::into_ref`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.into_ref)
-   [`Pin::get_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_mut)
-   [`Pin::get_unchecked_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_unchecked_mut)
-   [`Pin::static_ref`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.static_ref)
-   [`Pin::static_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.static_mut)

<a id="1.84.0-Cargo"></a>

## Cargo

-   [Stabilize MSRV-aware resolver config](rust-lang/cargo#14639)
-   [Stabilize resolver v3](rust-lang/cargo#14754)

<a id="1.84-Rustdoc"></a>

## Rustdoc

-   [rustdoc-search: improve type-driven search](rust-lang/rust#127589)

<a id="1.84.0-Compatibility-Notes"></a>

## Compatibility Notes

-   [Enable by default the `LSX` target feature for LoongArch Linux targets](rust-lang/rust#132140)
-   [The unstable `-Zprofile` flag (“gcov-style” coverage instrumentation) has been removed.](rust-lang/rust#131829) This does not affect the stable flags for coverage instrumentation (`-Cinstrument-coverage`) and profile-guided optimization (`-Cprofile-generate`, `-Cprofile-use`), which are unrelated and remain available.
-   Support for the target named `wasm32-wasi` has been removed as the target is now named `wasm32-wasip1`. This completes the [transition](rust-lang/compiler-team#607) [plan](rust-lang/compiler-team#695) for this target following [the introduction of `wasm32-wasip1`](rust-lang/rust#120468) in Rust 1.78. Compiler warnings on [use of `wasm32-wasi`](rust-lang/rust#126662) introduced in Rust 1.81 are now gone as well as the target is removed.
-   [The syntax `&pin (mut|const) T` is now parsed as a type which in theory could affect macro expansion results in some edge cases](rust-lang/rust#130635 (comment))
-   [Legacy syntax for calling `std::arch` functions is no longer permitted to declare items or bodies (such as closures, inline consts, or async blocks).](rust-lang/rust#130443 (comment))
-   [Declaring functions with a calling convention not supported on the current target now triggers a hard error](rust-lang/rust#129935)
-   [The next-generation trait solver is now enabled for coherence, fixing multiple soundness issues](rust-lang/rust#130654)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this MR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this MR, check this box

---

This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzOS45Ny4wIiwidXBkYXRlZEluVmVyIjoiMzkuMTAwLjEiLCJ0YXJnZXRCcmFuY2giOiJtYWluIiwibGFiZWxzIjpbIlJlbm92YXRlIEJvdCJdfQ==-->

Pkgsrc changes:
 * Adapt patches, one of the patched files were restructured upstream.
 * Checksum changes.

Upstream changes:

Version 1.84.1 (2025-01-30)
==========================

- [Fix ICE 132920 in duplicate-crate diagnostics.]
  (rust-lang/rust#133304)
- [Fix errors for overlapping impls in incremental rebuilds.]
  (rust-lang/rust#133828)
- [Fix slow compilation related to the next-generation trait solver.]
  (rust-lang/rust#135618)
- [Fix debuginfo when LLVM's location discriminator value limit is exceeded.]
  (rust-lang/rust#135643)
- Fixes for building Rust from source:
  - [Only try to distribute `llvm-objcopy` if llvm tools are enabled.]
    (rust-lang/rust#134240)
  - [Add Profile Override for Non-Git Sources.]
    (rust-lang/rust#135433)
  - [Resolve symlinks of LLVM tool binaries before copying them.]
    (rust-lang/rust#135585)
  - [Make it possible to use ci-rustc on tarball sources.]
    (rust-lang/rust#135722)

Version 1.84.0 (2025-01-09)
==========================

Language
--------
- [Allow `#[deny]` inside `#[forbid]` as a no-op]
  (rust-lang/rust#121560)
- [Show a warning when `-Ctarget-feature` is used to toggle features
  that can lead to unsoundness due to ABI mismatches]
  (rust-lang/rust#129884)
- [Use the next-generation trait solver in coherence]
  (rust-lang/rust#130654)
- [Allow coercions to drop the principal of trait objects]
  (rust-lang/rust#131857)
- [Support `/` as the path separator for `include!()` in all cases on Windows]
  (rust-lang/rust#125205)
- [Taking a raw ref (`raw (const|mut)`) of a deref of a pointer
  (`*ptr`) is now safe]
  (rust-lang/rust#129248)
- [Stabilize s390x inline assembly]
  (rust-lang/rust#131258)
- [Stabilize Arm64EC inline assembly]
  (rust-lang/rust#131781)
- [Lint against creating pointers to immediately dropped temporaries]
  (rust-lang/rust#128985)
- [Execute drop glue when unwinding in an `extern "C"` function]
  (rust-lang/rust#129582)

Compiler
--------
- [Add `--print host-tuple` flag to print the host target tuple
  and affirm the "target tuple" terminology over "target triple"]
  (rust-lang/rust#125579)
- [Declaring functions with a calling convention not supported on
  the current target now triggers a hard error]
  (rust-lang/rust#129935)
- [Set up indirect access to external data for
  `loongarch64-unknown-linux-{musl,ohos}`]
  (rust-lang/rust#131583)
- [Enable XRay instrumentation for LoongArch Linux targets]
  (rust-lang/rust#131818)
- [Extend the `unexpected_cfgs` lint to also warn in external macros]
  (rust-lang/rust#132577)
- [Stabilize WebAssembly `multivalue`, `reference-types`, and
  `tail-call` target features]
  (rust-lang/rust#131080)
- [Added Tier 2 support for the `wasm32v1-none` target]
  (rust-lang/rust#131487)

Libraries
---------
- [Implement `From<&mut {slice}>` for `Box/Rc/Arc<{slice}>`]
  (rust-lang/rust#129329)
- [Move `<float>::copysign`, `<float>::abs`, `<float>::signum` to `core`]
  (rust-lang/rust#131304)
- [Add `LowerExp` and `UpperExp` implementations to `NonZero`]
  (rust-lang/rust#131377)
- [Implement `FromStr` for `CString` and `TryFrom<CString>` for `String`]
  (rust-lang/rust#130608)
- [`std::os::darwin` has been made public]
  (rust-lang/rust#130635)

Stabilized APIs
---------------

- [`Ipv6Addr::is_unique_local`]
  (https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.is_unique_local)
- [`Ipv6Addr::is_unicast_link_local`]
  (https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.is_unicast_link_local)
- [`core::ptr::with_exposed_provenance`]
  (https://doc.rust-lang.org/stable/core/ptr/fn.with_exposed_provenance.html)
- [`core::ptr::with_exposed_provenance_mut`]
  (https://doc.rust-lang.org/stable/core/ptr/fn.with_exposed_provenance_mut.html)
- [`<ptr>::addr`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.addr)
- [`<ptr>::expose_provenance`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.expose_provenance)
- [`<ptr>::with_addr`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.with_addr)
- [`<ptr>::map_addr`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.map_addr)
- [`<int>::isqrt`]
  (https://doc.rust-lang.org/stable/core/primitive.i32.html#method.isqrt)
- [`<int>::checked_isqrt`]
  (https://doc.rust-lang.org/stable/core/primitive.i32.html#method.checked_isqrt)
- [`<uint>::isqrt`]
  (https://doc.rust-lang.org/stable/core/primitive.u32.html#method.isqrt)
- [`NonZero::isqrt`]
  (https://doc.rust-lang.org/stable/core/num/struct.NonZero.html#impl-NonZero%3Cu128%3E/method.isqrt)
- [`core::ptr::without_provenance`]
  (https://doc.rust-lang.org/stable/core/ptr/fn.without_provenance.html)
- [`core::ptr::without_provenance_mut`]
  (https://doc.rust-lang.org/stable/core/ptr/fn.without_provenance_mut.html)
- [`core::ptr::dangling`]
  (https://doc.rust-lang.org/stable/core/ptr/fn.dangling.html)
- [`core::ptr::dangling_mut`]
  (https://doc.rust-lang.org/stable/core/ptr/fn.dangling_mut.html)

These APIs are now stable in const contexts

- [`AtomicBool::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.from_ptr)
- [`AtomicPtr::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicPtr.html#method.from_ptr)
- [`AtomicU8::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU8.html#method.from_ptr)
- [`AtomicU16::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU16.html#method.from_ptr)
- [`AtomicU32::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU32.html#method.from_ptr)
- [`AtomicU64::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU64.html#method.from_ptr)
- [`AtomicUsize::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.from_ptr)
- [`AtomicI8::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI8.html#method.from_ptr)
- [`AtomicI16::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI16.html#method.from_ptr)
- [`AtomicI32::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI32.html#method.from_ptr)
- [`AtomicI64::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI64.html#method.from_ptr)
- [`AtomicIsize::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicIsize.html#method.from_ptr)
- [`<ptr>::is_null`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_null-1)
- [`<ptr>::as_ref`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.as_ref-1)
- [`<ptr>::as_mut`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.as_mut)
- [`Pin::new`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.new)
- [`Pin::new_unchecked`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.new_unchecked)
- [`Pin::get_ref`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_ref)
- [`Pin::into_ref`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.into_ref)
- [`Pin::get_mut`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_mut)
- [`Pin::get_unchecked_mut`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_unchecked_mut)
- [`Pin::static_ref`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.static_ref)
- [`Pin::static_mut`]
  (https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.static_mut)

Cargo
-----
- [Stabilize MSRV-aware resolver config]
  (rust-lang/cargo#14639)
- [Stabilize resolver v3]
  (rust-lang/cargo#14754)

Rustdoc
-------
- [rustdoc-search: improve type-driven search]
  (rust-lang/rust#127589)

Compatibility Notes
-------------------
- [Enable by default the `LSX` target feature for LoongArch Linux targets]
  (rust-lang/rust#132140)
- [The unstable `-Zprofile` flag ("gcov-style" coverage instrumentation)
  has been removed.](rust-lang/rust#131829)
  This does not affect the stable flags for coverage instrumentation
  (`-Cinstrument-coverage`) and profile-guided optimization
  (`-Cprofile-generate`, `-Cprofile-use`), which are unrelated and
  remain available.
- Support for the target named `wasm32-wasi` has been removed as
  the target is now named `wasm32-wasip1`. This completes the [transition]
  (rust-lang/compiler-team#607)
  [plan](rust-lang/compiler-team#695) for
  this target following [the introduction of `wasm32-wasip1`]
  (rust-lang/rust#120468) in Rust 1.78.
  Compiler warnings on [use of `wasm32-wasi`]
  (rust-lang/rust#126662)
  introduced in Rust 1.81 are now gone as well as the target is
  removed.
- [The syntax `&pin (mut|const) T` is now parsed as a type which
  in theory could affect macro expansion results in some edge cases]
  (rust-lang/rust#130635 (comment))
- [Legacy syntax for calling `std::arch` functions is no longer
  permitted to declare items or bodies (such as closures, inline
  consts, or async blocks).]
  (rust-lang/rust#130443 (comment))
- The `wasm32-unknown-emscripten` target's binary release of the
  standard library is now [built with the latest emsdk 3.1.68]
  (rust-lang/rust#131533), which fixes an
  ABI-incompatibility with Emscripten >= 3.1.42. If you are locally
  using a version of emsdk with an incompatible ABI (e.g. before
  3.1.42 or a future one), you should build your code with `-Zbuild-std`
  to ensure that `std` uses the correct ABI.
- [Declaring functions with a calling convention not supported on
  the current target now triggers a hard error]
  (rust-lang/rust#129935)
- [The next-generation trait solver is now enabled for coherence,
  fixing multiple soundness issues]
  (rust-lang/rust#130654)

…ingjubilee

forbid toggling x87 and fpregs on hard-float targets

Part of rust-lang/rust#116344, follow-up to rust-lang/rust#129884:

The `x87`  target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](rust-lang/rust#130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).

Also fixes rust-lang/rust#132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.

The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.

r? `@workingjubilee`

…ingjubilee

forbid toggling x87 and fpregs on hard-float targets

Part of rust-lang/rust#116344, follow-up to rust-lang/rust#129884:

The `x87`  target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](rust-lang/rust#130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).

Also fixes rust-lang/rust#132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.

The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.

r? `@workingjubilee`