From be5d72129e33d2cadb7fa003395eccd986447833 Mon Sep 17 00:00:00 2001
From: Ximin Luo <infinity0@pwned.gg>
Date: Sun, 11 Apr 2021 14:02:28 +0100
Subject: [PATCH] bootstrap: check local_rebuild before adding --cfg=bootstrap,
 closes #84057

---
 src/bootstrap/compile.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 8244c7710ab7..66a88e85fea3 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -462,11 +462,13 @@ impl Step for StartupObjects {
             let dst_file = &dst_dir.join(file.to_string() + ".o");
             if !up_to_date(src_file, dst_file) {
                 let mut cmd = Command::new(&builder.initial_rustc);
+                cmd.env("RUSTC_BOOTSTRAP", "1");
+                if !builder.local_rebuild {
+                    // a local_rebuild compiler already has stage1 features
+                    cmd.arg("--cfg").arg("bootstrap");
+                }
                 builder.run(
-                    cmd.env("RUSTC_BOOTSTRAP", "1")
-                        .arg("--cfg")
-                        .arg("bootstrap")
-                        .arg("--target")
+                    cmd.arg("--target")
                         .arg(target.rustc_target_arg())
                         .arg("--emit=obj")
                         .arg("-o")