Auto merge of #77975 - bjorn3:cg_clif_subtree3, r=Mark-Simulacrum

Add cg_clif as optional codegen backend

Rustc_codegen_cranelift is an alternative codegen backend for rustc based on Cranelift. It has the potential to improve compilation times in debug mode. In my experience the compile time improvements over debug mode LLVM for a clean build are about 20-30% in most cases.

This PR adds cg_clif as optional codegen backend. By default it is only enabled for `./x.py check`. It can be enabled for `./x.py build` too by adding `cranelift` to the `rust.codegen-backends` array in `config.toml`.

MCP: rust-lang/compiler-team#270

r? `@Mark-Simulacrum`

Author: bors

Cargo.toml

@@ -31,6 +31,7 @@ members = [
 ]
 exclude = [
   "build",
+  "compiler/rustc_codegen_cranelift",
   # HACK(eddyb) This hardcodes the fact that our CI uses `/checkout/obj`.
   "obj",
 ]

compiler/rustc_codegen_cranelift/.gitattributes

@@ -0,0 +1 @@
+* text=auto eol=lf