From b79cbf32ea6cb223bebc5f731494565f7b880e36 Mon Sep 17 00:00:00 2001
From: Ryan Burns <rtburns@protonmail.com>
Date: Tue, 2 Jan 2024 20:29:57 -0800
Subject: [PATCH] freebsd.libc: fix build with LLVM 16+

---
 pkgs/os-specific/bsd/freebsd/default.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/os-specific/bsd/freebsd/default.nix b/pkgs/os-specific/bsd/freebsd/default.nix
index ff9f4d911f03..398b2ff6fa6d 100644
--- a/pkgs/os-specific/bsd/freebsd/default.nix
+++ b/pkgs/os-specific/bsd/freebsd/default.nix
@@ -717,6 +717,10 @@ in makeScopeWithSplicing' {
     buildInputs = with self; [ include csu ];
     env.NIX_CFLAGS_COMPILE = "-B${self.csu}/lib";
 
+    # Suppress lld >= 16 undefined version errors
+    # https://github.com/freebsd/freebsd-src/commit/2ba84b4bcdd6012e8cfbf8a0d060a4438623a638
+    env.NIX_LDFLAGS = lib.optionalString (stdenv.targetPlatform.linker == "lld") "--undefined-version";
+
     makeFlags = [
       "STRIP=-s" # flag to install, not command
       # lib/libc/gen/getgrent.c has sketchy cast from `void *` to enum