[PATCH v2 3/5] rust: Enable RUSTC_BOOTSTRAP to use nightly features during rust oe-selftest.

[Yash.Shinde@windriver.com]

From: Yash Shinde <Yash.Shinde@windriver.com>

Fixes: error: the option `Z` is only accepted on the nightly compiler

When rust.channel is set to either beta or stable, we can't use
nightly features on bootstrap without RUSTC_BOOTSTRAP.
Set RUSTC_BOOTSTRAP=1 to use nightly features on stable or beta.

Signed-off-by: Yash Shinde <Yash.Shinde@windriver.com>
---
 .../rust/files/rustc-bootstrap.patch          | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 meta/recipes-devtools/rust/files/rustc-bootstrap.patch

diff --git a/meta/recipes-devtools/rust/files/rustc-bootstrap.patch b/meta/recipes-devtools/rust/files/rustc-bootstrap.patch
new file mode 100644
index 0000000000..406fc610bb
--- /dev/null
+++ b/meta/recipes-devtools/rust/files/rustc-bootstrap.patch
@@ -0,0 +1,21 @@
+When rust.channel is set to either beta or stable, we can't use
+nightly features on bootstrap without RUSTC_BOOTSTRAP. Set RUSTC_BOOTSTRAP=1
+to use nightly features on stable or beta.
+
+Upstream-Status: Backport [https://github.com/rust-lang/rust/pull/119619/commits/8aa7dd06f6e50621dc10f9f9490681be8a45876f]
+
+Signed-off-by: onur-ozkan <work@onurozkan.dev>
+Signed-off-by: Yash Shinde <Yash.Shinde@windriver.com>
+---
+diff --git a/src/bootstrap/synthetic_targets.rs b/ src/bootstrap/synthetic_targets.rs
+index d2c65b740da..45baf56f46b 100644
+--- a/src/bootstrap/synthetic_targets.rs
++++ b/src/bootstrap/synthetic_targets.rs
+@@ -59,6 +59,7 @@ fn create_synthetic_target(
+     let mut cmd = Command::new(builder.rustc(compiler));
+     cmd.arg("--target").arg(base.rustc_target_arg());
+     cmd.args(["-Zunstable-options", "--print", "target-spec-json"]);
++    cmd.env("RUSTC_BOOTSTRAP", "1");
+     cmd.stdout(Stdio::piped());
+
+     let output = cmd.spawn().unwrap().wait_with_output().unwrap();
-- 
2.43.0