…count check

Co-authored-by: Mara Bos <m-ou.se@m-ou.se>

Add implementations of `AsFd` for `&T` and `&mut T`, so that users can
write code like this:

```rust
pub fn fchown<F: AsFd>(fd: F, uid: Option<u32>, gid: Option<u32>) -> io::Result<()> {
```

with `fd: F` rather than `fd: &F`.

And similar for `AsHandle` and `AsSocket` on Windows.

Also, adjust the `fchown` example to pass the file by reference. The
code can work either way now, but passing by reference is more likely
to be what users will want to do.

This is an alternative to rust-lang#93869, and is a simpler way to achieve the
same goals: users don't need to pass borrowed-`BorrowedFd` arguments,
and it prevents a pitfall in the case where users write `fd: F` instead
of `fd: &F`.

…ent_dir

the function was moved from `Crate` to `Map` in db9fea5 but the
docs weren't updated

This option introduced in rust-lang#15820 allows a custom crate to be imported in
the place of std, but with the name std. I don't think there is any
value to this. At most it is confusing users of a driver that uses this option. There are no users of
this option on github. If anyone still needs it, they can emulate it
injecting #![no_core] in addition to their own prelude.

…nput, r=m-ou-se

Rename `FilenameTooLong` to `InvalidFilename` and also use it for Windows' `ERROR_INVALID_NAME`

Address rust-lang#90940 (comment)
`ERROR_INVALID_NAME` (i.e. "The filename, directory name, or volume label syntax is incorrect") happens if we pass an invalid filename, directory name, or label syntax, so mapping as `InvalidInput` is reasonable to me.

… r=jackh726

Make `span_extend_to_prev_str()` more robust

Fixes rust-lang#91560. The logic in `span_extend_to_prev_str()` is currently quite brittle and fails if there is extra whitespace or something else in between, and it also should return an `Option` but doesn't currently.

Remove some unused functionality

* Remove the `alt_std_name` option
* Remove the everybody loops pass
* Make two functions private

…c-info, r=Amanieu

Add missing platform-specific information on current_dir and set_current_dir

Fixes rust-lang#93598.

…=CraftSpider

rustdoc-json: Add some tests for typealias item

r? `@CraftSpider`

Improves rust-lang#81359

The test's arn't pretty, and I think eventually we need a better way of doing repeated tests on a deeply nested path,
without repeating the way to get to that path

`@rustbot` modify labels: +A-rustdoc-json +T-rustdoc +A-rustdoc +A-testsuite

…h, r=Amanieu

Split `pauth` target feature

Per discussion on rust-lang#86941 we'd like to split `pauth` into `paca` and `pacg` in order to better support possible future environments that only have the keys available for address or generic authentication. At the moment LLVM has the one `pauth` target_feature while Linux presents separate `paca` and `pacg` flags for feature detection.

Because the use of [target_feature](https://rust-lang.github.io/rfcs/2045-target-feature.html) will "allow the compiler to generate code under the assumption that this code will only be reached in hosts that support the feature", it does not make sense to simply translate `paca` into the LLVM feature `pauth`, as it will generate code as if `pacg` is available.

To accommodate this we error if only one of the two features is present. If LLVM splits them in the future we can remove this restriction without making a breaking change.

r? `@Amanieu`

…shtriplett

Add a `process_group` method to UNIX `CommandExt`

- Tracking issue: rust-lang#93857
- RFC: rust-lang/rfcs#3228

Add a `process_group` method to `std::os::unix::process::CommandExt` that
allows setting the process group id (i.e. calling `setpgid`) in the child, thus
enabling users to set process groups while leveraging the `posix_spawn` fast
path.

…or-ref, r=joshtriplett

Implement `AsFd` for `&T` and `&mut T`.

Add implementations of `AsFd` for `&T` and `&mut T`, so that users can
write code like this:

```rust
pub fn fchown<F: AsFd>(fd: F, uid: Option<u32>, gid: Option<u32>) -> io::Result<()> {
```

with `fd: F` rather than `fd: &F`.

And similar for `AsHandle` and `AsSocket` on Windows.

Also, adjust the `fchown` example to pass the file by reference. The
code can work either way now, but passing by reference is more likely
to be what users will want to do.

This is an alternative to rust-lang#93869, and is a simpler way to achieve the
same goals: users don't need to pass borrowed-`BorrowedFd` arguments,
and it prevents a pitfall in the case where users write `fd: F` instead
of `fd: &F`.

r? `@joshtriplett`

Fix typo: explicitely -> explicitly

fix mention of moved function in `rustc_hir` docs

The function was moved from `Crate` to `Map` in db9fea5 but these docs weren't updated