From 2561e37d0e043735cfe54d6c3574c010e445e8a2 Mon Sep 17 00:00:00 2001
From: Audrey Dutcher <audrey@rhelmot.io>
Date: Thu, 20 Feb 2025 16:43:36 -0700
Subject: [PATCH] zlib-ng: fix build on FreeBSD

---
 pkgs/by-name/zl/zlib-ng/package.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/by-name/zl/zlib-ng/package.nix b/pkgs/by-name/zl/zlib-ng/package.nix
index 70935d20f519..86c6ccd48e8a 100644
--- a/pkgs/by-name/zl/zlib-ng/package.nix
+++ b/pkgs/by-name/zl/zlib-ng/package.nix
@@ -32,6 +32,12 @@ stdenv.mkDerivation rec {
     pkg-config
   ];
 
+  env = lib.optionalAttrs stdenv.hostPlatform.isFreeBSD {
+    # This can be removed when we switch to libcxx from llvm 20
+    # https://github.com/llvm/llvm-project/pull/122361
+    NIX_CFLAGS_COMPILE = "-D_XOPEN_SOURCE=700";
+  };
+
   buildInputs = [ gtest ];
 
   cmakeFlags = [