Auto merge of #128002 - matthiaskrgr:rollup-21p0cue, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #127463 ( use precompiled rustdoc with CI rustc)
 - #127779 (Add a hook for `should_codegen_locally`)
 - #127843 (unix: document unsafety for std `sig{action,altstack}`)
 - #127873 (kmc-solid: `#![forbid(unsafe_op_in_unsafe_fn)]`)
 - #127917 (match lowering: Split `finalize_or_candidate` into more coherent methods)
 - #127964 (run_make_support: skip rustfmt for lib.rs)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_middle/src/hooks/mod.rs

@@ -103,6 +103,10 @@ declare_hooks! {
 
     /// Create a list-like THIR representation for debugging.
     hook thir_flat(key: LocalDefId) -> String;
+
+    /// Returns `true` if we should codegen an instance in the local crate, or returns `false` if we
+    /// can just link to the upstream crate and therefore don't need a mono item.
+    hook should_codegen_locally(instance: crate::ty::Instance<'tcx>) -> bool;
 }
 
 #[cold]