From cac46994c9db9531813c9a80b5b1ca9c26f05240 Mon Sep 17 00:00:00 2001
From: Thomas <9749173+uhthomas@users.noreply.github.com>
Date: Tue, 19 Apr 2022 16:54:23 +0100
Subject: [PATCH] Pass '-undefined error' non sysroot ldflag on macOS (#894)

---
 foreign_cc/built_tools/make_build.bzl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/foreign_cc/built_tools/make_build.bzl b/foreign_cc/built_tools/make_build.bzl
index cc15a55a..90667fcf 100644
--- a/foreign_cc/built_tools/make_build.bzl
+++ b/foreign_cc/built_tools/make_build.bzl
@@ -71,6 +71,9 @@ def _make_tool_impl(ctx):
         if absolute_ar == "libtool" or absolute_ar.endswith("/libtool"):
             arflags.append("-o")
 
+        if os_name(ctx) == "macos":
+            non_sysroot_ldflags += ["-undefined", "error"]
+
         env.update({
             "AR": absolute_ar,
             "ARFLAGS": _join_flags_list(ctx.workspace_name, arflags),