From 8df4517d370b0c543a01ba38b63e1d5a4104b035 Mon Sep 17 00:00:00 2001
From: Daniel Wagner-Hall <dwagnerhall@apple.com>
Date: Wed, 23 Mar 2022 14:59:16 +0000
Subject: [PATCH] Add NUM_JOBS env var to cargo build scripts (#1216)

Some build scripts use this. It is documented at
https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts
---
 cargo/cargo_build_script.bzl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cargo/cargo_build_script.bzl b/cargo/cargo_build_script.bzl
index c619b92f49..d9dae0f1e3 100644
--- a/cargo/cargo_build_script.bzl
+++ b/cargo/cargo_build_script.bzl
@@ -83,6 +83,7 @@ def _build_script_impl(ctx):
         "CARGO_MANIFEST_DIR": manifest_dir,
         "CARGO_PKG_NAME": pkg_name,
         "HOST": toolchain.exec_triple,
+        "NUM_JOBS": "1",
         "OPT_LEVEL": compilation_mode_opt_level,
         "RUSTC": toolchain.rustc.path,
         "TARGET": toolchain.target_flag_value,