From ab1f321fa51c110e70236895272e5514a4564117 Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@gmail.com>
Date: Thu, 21 Mar 2024 06:10:47 +0000
Subject: [PATCH] Look for underscored name in rust 1.79

See https://github.com/rust-lang/cargo/pull/12783.
---
 Cargo.toml |  1 +
 build.rs   | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 609307b..28427c3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,4 +24,5 @@ anyhow = "1.0.72"
 cargo_metadata = "0.18.0"
 prettyplease = "0.2.10"
 quote = "1.0.29"
+rustversion = "1.0"
 syn = { version = "2.0.26", features = ["full"] }
diff --git a/build.rs b/build.rs
index c145857..005d6c4 100644
--- a/build.rs
+++ b/build.rs
@@ -59,6 +59,14 @@ mod llvm {
 
     impl Generator {
         pub fn parse_llvm_sys_crate(&mut self) -> Result<&mut Self, Error> {
+            // See https://github.com/rust-lang/cargo/pull/12783.
+
+            #[rustversion::before(1.79)]
+            const LLVM_SYS_CRATE_TARGET: &str = "llvm-sys";
+
+            #[rustversion::since(1.79)]
+            const LLVM_SYS_CRATE_TARGET: &str = "llvm_sys";
+
             let metadata = MetadataCommand::new()
                 .exec()
                 .context("Unable to get crate metadata")?;
@@ -72,7 +80,7 @@ mod llvm {
                             targets
                                 .into_iter()
                                 .find_map(|Target { name, src_path, .. }| {
-                                    (name == "llvm-sys").then_some(src_path)
+                                    (name == LLVM_SYS_CRATE_TARGET).then_some(src_path)
                                 })
                         })
                         .flatten()