nixpkgs/pkgs/servers/sql/postgresql/ext/vectorchord/0001-read-clang-flags-from-environment.diff

diff --git a/crates/simd/build.rs b/crates/simd/build.rs
index 12ce198..aed5588 100644
--- a/crates/simd/build.rs
+++ b/crates/simd/build.rs
@@ -17,17 +17,24 @@ use std::error::Error;
 
 fn main() -> Result<(), Box<dyn Error>> {
     println!("cargo::rerun-if-changed=cshim");
+    println!("cargo:rerun-if-env-changed=BINDGEN_EXTRA_CLANG_ARGS");
     let target_arch = var("CARGO_CFG_TARGET_ARCH")?;
     match target_arch.as_str() {
         "aarch64" => {
             let mut build = cc::Build::new();
             build.file("./cshim/aarch64.c");
+            build.compiler("@clang@");
+            // read env var set by rustPlatform.bindgenHook
+            build.try_flags_from_environment("BINDGEN_EXTRA_CLANG_ARGS").expect("the BINDGEN_EXTRA_CLANG_ARGS environment variable must be specified and UTF-8");
             build.opt_level(3);
             build.compile("simd_cshim");
         }
         "x86_64" => {
             let mut build = cc::Build::new();
             build.file("./cshim/x86_64.c");
+            build.compiler("@clang@");
+            // read env var set by rustPlatform.bindgenHook
+            build.try_flags_from_environment("BINDGEN_EXTRA_CLANG_ARGS").expect("the BINDGEN_EXTRA_CLANG_ARGS environment variable must be specified and UTF-8");
             build.opt_level(3);
             build.compile("simd_cshim");
         }