From e09a8bd70c4804234af900f19fbb883045ba8d0d Mon Sep 17 00:00:00 2001
From: Mark Simulacrum <mark.simulacrum@gmail.com>
Date: Sun, 28 Jan 2018 17:09:47 -0700
Subject: [PATCH] Add per-stage RUSTFLAGS: RUSTFLAGS_STAGE_{0,1,2} and
 RUSTFLAGS_STAGE_NOT_0

Fixes #47658.
---
 src/bootstrap/builder.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 79058984b1352..1272643edd259 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -469,6 +469,18 @@ impl<'a> Builder<'a> {
             stage = compiler.stage;
         }
 
+        let mut extra_args = env::var(&format!("RUSTFLAGS_STAGE_{}", stage)).unwrap_or_default();
+        if stage != 0 {
+            let s = env::var("RUSTFLAGS_STAGE_NOT_0").unwrap_or_default();
+            extra_args.push_str(" ");
+            extra_args.push_str(&s);
+        }
+
+        if !extra_args.is_empty() {
+            cargo.env("RUSTFLAGS",
+                format!("{} {}", env::var("RUSTFLAGS").unwrap_or_default(), extra_args));
+        }
+
         // Customize the compiler we're running. Specify the compiler to cargo
         // as our shim and then pass it some various options used to configure
         // how the actual compiler itself is called.