bootstrap: make copying linker binaries conditional

Author: P1n3appl3

src/bootstrap/compile.rs

@@ -161,14 +161,15 @@ impl Step for Std {
         // The LLD wrappers and `rust-lld` are self-contained linking components that can be
         // necessary to link the stdlib on some targets. We'll also need to copy these binaries to
         // the `stage0-sysroot` to ensure the linker is found when bootstrapping on such a target.
-        if compiler.stage == 0 && compiler.host == builder.config.build {
+        let src_sysroot_bin = builder
+            .rustc_snapshot_sysroot()
+            .join("lib")
+            .join("rustlib")
+            .join(compiler.host.triple)
+            .join("bin");
+        if compiler.stage == 0 && compiler.host == builder.config.build && src_sysroot_bin.exists()
+        {
             // We want to copy the host `bin` folder within the `rustlib` folder in the sysroot.
-            let src_sysroot_bin = builder
-                .rustc_snapshot_sysroot()
-                .join("lib")
-                .join("rustlib")
-                .join(&compiler.host.triple)
-                .join("bin");
             let target_sysroot_bin =
                 builder.sysroot_libdir(compiler, target).parent().unwrap().join("bin");
             t!(fs::create_dir_all(&target_sysroot_bin));