From fb2418260e4a4183623faa05a54594a8abe5d6a0 Mon Sep 17 00:00:00 2001
From: Weijia Wang <9713184+wegank@users.noreply.github.com>
Date: Tue, 20 Jan 2026 22:45:11 +0100
Subject: [PATCH] python3Packages.klayout: fix darwin build

---
 pkgs/development/python-modules/klayout/default.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/python-modules/klayout/default.nix b/pkgs/development/python-modules/klayout/default.nix
index 08a06b34e9b5..21028747e798 100644
--- a/pkgs/development/python-modules/klayout/default.nix
+++ b/pkgs/development/python-modules/klayout/default.nix
@@ -38,6 +38,10 @@ buildPythonPackage rec {
     fixDarwinDylibNames
   ];
 
+  # Ensure that there is enough space for the `fixDarwinDylibNames` hook to
+  # update the install names of the output dylibs.
+  env.NIX_LDFLAGS = lib.optionalString stdenv.hostPlatform.isDarwin "-headerpad_max_install_names";
+
   pythonImportsCheck = [ "klayout" ];
 
   meta = {