rust/library/std_detect/Cargo.toml, branch perf-tmp

`std_detect`: Use `rustc-std-workspace-*` to pull in `compiler-builtins`

2025-08-19T18:17:35+00:00

https://github.com/rust-lang/rust/pull/145489 changed `std_detect` to no longer depend on `cfg-if`, which meant it no longer indirectly pulled in `rustc-std-workspace-core` via `cfg-if`. That caused it to no longer depend on `compiler-builtins`. Change `std_detect` to use `rustc-std-workspace-core` and `rustc-std-workspace-alloc`, to integrate with the rustc workspace. This also pulls in `compiler-builtins` via `rustc-std-workspace-core`. Closes: https://github.com/rust-lang/rust/issues/145594

library: Migrate from `cfg_if` to `cfg_select`

2025-08-16T12:28:31+00:00

Migrate the standard library from using the external `cfg_if` crate to using the now-built-in `cfg_select` macro. This does not yet eliminate the dependency from `library/std/Cargo.toml`, because while the standard library itself no longer uses `cfg_if`, it also incorporates the `backtrace` crate, which does. Migration assisted by the following vim command (after selecting the full `cfg_if!` invocation): ``` '<,'>s/\(cfg_if::\)\?cfg_if/cfg_select/ | '<,'>s/^\( *\)} else {/\1}\r\1_ => {/c | '<,'>s/^\( *\)} else if #\[cfg(\(.*\))\] /\1}\r\1\2 => /e | '<,'>s/if #\[cfg(\(.*\))\] {/\1 => {/e ``` This is imperfect, but substantially accelerated the process. This prompts for confirmation on the `} else {` since that can also appear inside one of the arms. This also requires manual intervention to handle any multi-line conditions.

Make `std_detect` a direct dependency of `std`

2025-07-22T18:17:23+00:00

Move `std_detect` from `library/stdarch` to `library`

2025-07-22T18:17:06+00:00