From 9e99a66c24509c9e4d5078ca6a1b1a222c248ec2 Mon Sep 17 00:00:00 2001
From: Rok Garbas <rok@garbas.si>
Date: Thu, 4 Jun 2015 19:26:30 +0200
Subject: [PATCH] cygwin: make flex building on cygwin

---
 pkgs/development/tools/parsing/flex/2.5.39.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/tools/parsing/flex/2.5.39.nix b/pkgs/development/tools/parsing/flex/2.5.39.nix
index f12f89f6e24..93d54803e7c 100644
--- a/pkgs/development/tools/parsing/flex/2.5.39.nix
+++ b/pkgs/development/tools/parsing/flex/2.5.39.nix
@@ -12,7 +12,7 @@ stdenv.mkDerivation {
 
   propagatedNativeBuildInputs = [ m4 ];
 
-  postConfigure = stdenv.lib.optionalString stdenv.isDarwin ''
+  postConfigure = stdenv.lib.optionalString (stdenv.isDarwin || stdenv.isCygwin) ''
     sed -i Makefile -e 's/-no-undefined//;'
   '';