Auto merge of #88000 - bjorn3:fix_cg_llvm_clif_compile, r=Mark-Simulacrum

Fix compiling other codegen backends when llvm is enabled

Extracted from #81746

Without this change rustbuild will not pass the required linker argument to find libllvm. While other backends likely don't use libllvm, it is necessary to be able to link against rustc_driver as the llvm backend is linked into it.

src/bootstrap/builder.rs

@@ -1288,7 +1288,7 @@ pub fn cargo(
         // requirement, but the `-L` library path is not propagated across
         // separate Cargo projects. We can add LLVM's library path to the
         // platform-specific environment variable as a workaround.
-        if mode == Mode::ToolRustc {
+        if mode == Mode::ToolRustc || mode == Mode::Codegen {
             if let Some(llvm_config) = self.llvm_config(target) {
                 let llvm_libdir = output(Command::new(&llvm_config).arg("--libdir"));
                 add_link_lib_path(vec![llvm_libdir.trim().into()], &mut cargo);

src/bootstrap/compile.rs

@@ -806,6 +806,10 @@ fn run(self, builder: &Builder<'_>) {
 
         let tmp_stamp = out_dir.join(".tmp.stamp");
 
+        builder.info(&format!(
+            "Building stage{} codegen backend {} ({} -> {})",
+            compiler.stage, backend, &compiler.host, target
+        ));
         let files = run_cargo(builder, cargo, vec![], &tmp_stamp, vec![], false);
         if builder.config.dry_run {
             return;