From ba5231751811386387746bafb1bb791be5057132 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Sun, 10 Mar 2024 22:10:05 +0100
Subject: [PATCH] Add code comment about the `--backend` option usage

---
 build_system/src/config.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/build_system/src/config.rs b/build_system/src/config.rs
index 34c92a3485e..0a7258958e7 100644
--- a/build_system/src/config.rs
+++ b/build_system/src/config.rs
@@ -398,6 +398,8 @@ pub fn setup(
             .display()
             .to_string();
         if let Some(backend) = &self.backend {
+            // This option is only used in the rust compiler testsuite. The sysroot is handled
+            // by its build system directly so no need to set it ourselves.
             rustflags.push(format!("-Zcodegen-backend={}", backend));
         } else {
             rustflags.extend_from_slice(&[