From 2c437af02087e5c582b131d9d6940389325537a6 Mon Sep 17 00:00:00 2001
From: David McFarland <corngood@gmail.com>
Date: Mon, 29 Sep 2025 16:20:35 -0300
Subject: [PATCH] isl: fix cygwin build

---
 pkgs/development/libraries/isl/generic.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkgs/development/libraries/isl/generic.nix b/pkgs/development/libraries/isl/generic.nix
index 0ffec59b278c..8988e8faf982 100644
--- a/pkgs/development/libraries/isl/generic.nix
+++ b/pkgs/development/libraries/isl/generic.nix
@@ -42,6 +42,8 @@ stdenv.mkDerivation {
 
   enableParallelBuilding = true;
 
+  makeFlags = lib.optional stdenv.hostPlatform.isPE "LDFLAGS=-no-undefined";
+
   meta = {
     homepage = "https://libisl.sourceforge.io/";
     license = lib.licenses.lgpl21;