Co-authored-by: Ralf Jung <post@ralfj.de>

Currently, when building with `build-std`, some library build scripts
check properties of the target by inspecting the target triple at
`env::TARGET`, which is simply set to the filename of the JSON file
when using JSON target files.

This patch alters these build scripts to use `env::CARGO_CFG_*` to
fetch target information instead, allowing JSON target files
describing platforms without `restricted_std` to build correctly when
using `-Z build-std`.

Fixes wg-cargo-std-aware/rust-lang#60.

This refactors run.sh to never override an explicit $CODEGEN_BACKENDS if
set in the build.

This includes a change to the upstream build_fuchsia_from_rust_ci script
that builds a minimal set of tests, to improve coverage on this builder.

Related to rust-lang#117925

This reverts commit 31ecf34.

Co-authored-by: Ryan Levick <me@ryanlevick.com>

References refer to allocated objects

Partially addresses rust-lang/unsafe-code-guidelines#465

…trochenkov

Suppress unhelpful diagnostics for unresolved top level attributes

Fixes rust-lang#118455, unresolved top level attribute error didn't imported prelude and already have emitted an error, report builtin macro and attributes error by the way, so `check_invalid_crate_level_attr` in can ignore them.

Also fixes rust-lang#89566, fixes rust-lang#67107.

r? ```@petrochenkov```

Reject infinitely-sized reads from io::Repeat

These calls would always run out of memory.

Related to rust-lang#117925

Add support for custom JSON targets when using build-std.

Currently, when building with `build-std`, some library build scripts check properties of the target by inspecting the target triple at `env::TARGET`, which is simply set to the filename of the JSON file when using JSON target files.

This patch alters these build scripts to use `env::CARGO_CFG_*` to fetch target information instead, allowing JSON target files describing platforms without `restricted_std` to build correctly when using `-Z build-std`. There are some weak assertions here (for example, `nintendo && newlib`), however this seems at least a marginal improvement on the existing solution.

Fixes rust-lang/wg-cargo-std-aware#60.

…ark-Simulacrum

Bump Fuchsia, build tests, and use 8 core bots

- Build Fuchsia on 8 cores instead of 16
- Skip building cranelift for Fuchsia
- Bump Fuchsia (includes building tests)

This includes a change to the upstream build_fuchsia_from_rust_ci script that builds a minimal set of tests, to improve coverage on this builder. This would have caught rust-lang/rust-clippy#11952 and rust-lang#119593.

See prior discussion on rust-lang#119400 about building on 8 cores instead of 16. This PR combines changes from that and rust-lang#119399, plus clean up.

r? `````@Mark-Simulacrum`````

raw pointer metadata API: data address -> data pointer

A pointer consists of [more than just an address](rust-lang/rfcs#3559), so let's not equate "pointer" and "address" in these docs.

Revert outdated version of "Add the wasm32-wasi-preview2 target"

An outdated version of rust-lang#119616 was merged in rollup rust-lang#120309.
This reverts those changes to enable rust-lang#119616 to “retain the intended diff” after a rebase.
`@rylev` has agreed that this would be the cleanest approach with respect to the history.
Unblocks rust-lang#119616.

r? `@petrochenkov` or compiler or libs

…ement, r=fmease

Fixes footnote handling in rustdoc

Fixes rust-lang#100638.

You can now declare footnotes like this:

```rust
//! Reference to footnotes A[^1], B[^2] and C[^3].
//!
//! [^1]: Footnote A.
//! [^2]: Footnote B.
//! [^3]: Footnote C.
```

r? `@notriddle`