From d9ff1c23abd34f89398921e704f8ef8371a2f308 Mon Sep 17 00:00:00 2001
From: Taiki Endo <te316e89@gmail.com>
Date: Sun, 22 Nov 2020 12:01:11 +0900
Subject: [PATCH] Do not fail to compile if autocfg unable to determine rustc
 version

---
 crossbeam-utils/build.rs | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/crossbeam-utils/build.rs b/crossbeam-utils/build.rs
index 86c40ab9b..3e5102183 100644
--- a/crossbeam-utils/build.rs
+++ b/crossbeam-utils/build.rs
@@ -1,5 +1,20 @@
+use autocfg::AutoCfg;
+
+// The rustc-cfg strings below are *not* public API. Please let us know by
+// opening a GitHub issue if your build environment requires some way to enable
+// these cfgs other than by executing our build script.
 fn main() {
-    let cfg = autocfg::new();
+    let cfg = match AutoCfg::new() {
+        Ok(cfg) => cfg,
+        Err(e) => {
+            println!(
+                "cargo:warning=crossbeam-utils: unable to determine rustc version: {}",
+                e
+            );
+            return;
+        }
+    };
+
     cfg.emit_type_cfg("core::sync::atomic::AtomicU8", "has_atomic_u8");
     cfg.emit_type_cfg("core::sync::atomic::AtomicU16", "has_atomic_u16");
     cfg.emit_type_cfg("core::sync::atomic::AtomicU32", "has_atomic_u32");