From d58a46a422b731118aa42188ffdc39a9597bdcf4 Mon Sep 17 00:00:00 2001
From: David McFarland <corngood@gmail.com>
Date: Mon, 29 Sep 2025 15:54:35 -0300
Subject: [PATCH] mpfr: fix cygwin build

---
 pkgs/by-name/mp/mpfr/package.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pkgs/by-name/mp/mpfr/package.nix b/pkgs/by-name/mp/mpfr/package.nix
index 7dc402720c8a..91199418e254 100644
--- a/pkgs/by-name/mp/mpfr/package.nix
+++ b/pkgs/by-name/mp/mpfr/package.nix
@@ -50,7 +50,8 @@ stdenv.mkDerivation rec {
       # Without this, the `tget_set_d128` test experiences a link
       # error due to missing `__dpd_trunctdkf`.
       "--disable-decimal-float"
-    ];
+    ]
+    ++ lib.optional stdenv.hostPlatform.isPE "LDFLAGS=-Wl,-no-undefined";
 
   doCheck = true; # not cross;