Add documentation links to the original type for various OS-specific
extension traits and normalize the language for introducing such traits.
Also, remove some outdated comments around the extension trait
definitions.
* Remove the deprecated `CharRange` type which was forgotten to be removed
awhile back.
* Stabilize the `os::$platform::raw::pthread_t` type which was intended to be
stabilized as part of #32804
This commit is an implementation of [RFC 1415][rfc] which deprecates all types
in the `std::os::*::raw` modules.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/1415-trim-std-os.md
Many of the types in these modules don't actually have a canonical platform
representation, for example the definition of `stat` on 32-bit Linux will change
depending on whether C code is compiled with LFS support or not. Unfortunately
the current types in `std::os::*::raw` are billed as "compatible with C", which
in light of this means it isn't really possible.
To make matters worse, platforms like Android sometimes define these types as
*smaller* than the way they're actually represented in the `stat` structure
itself. This means that when methods like `DirEntry::ino` are called on Android
the result may be truncated as we're tied to returning a `ino_t` type, not the
underlying type.
The commit here incorporates two backwards-compatible components:
* Deprecate all `raw` types that aren't in `std::os::raw`
* Expand the `std::os::*::fs::MetadataExt` trait on all platforms for method
accessors of all fields. The fields now returned widened types which are the
same across platforms (consistency across platforms is not required, however,
it's just convenient).
and two also backwards-incompatible components:
* Change the definition of all `std::os::*::raw` type aliases to
correspond to the newly widened types that are being returned on each
platform.
* Change the definition of `std::os::*::raw::stat` on Linux to match the LFS
definitions rather than the standard ones.
The breaking changes here will specifically break code that assumes that `libc`
and `std` agree on the definition of `std::os::*::raw` types, or that the `std`
types are faithful representations of the types in C. An [audit] has been
performed of crates.io to determine the fallout which was determined two be
minimal, with the two found cases of breakage having been fixed now.
[audit]: https://github.com/rust-lang/rfcs/pull/1415#issuecomment-180645582
---
Ok, so after all that, we're finally able to support LFS on Linux! This commit
then simultaneously starts using `stat64` and friends on Linux to ensure that we
can open >4GB files on 32-bit Linux. Yay!
Closes#28978Closes#30050Closes#31549
