From fa418d26fc72bdfb4e7f4e515c120b161071e5ae Mon Sep 17 00:00:00 2001
From: David McFarland <corngood@gmail.com>
Date: Fri, 12 Sep 2025 15:16:07 -0300
Subject: [PATCH] gnugrep: fix cygwin build

---
 pkgs/tools/text/gnugrep/default.nix | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkgs/tools/text/gnugrep/default.nix b/pkgs/tools/text/gnugrep/default.nix
index e32a5a867c0f..51a7f2fe21d6 100644
--- a/pkgs/tools/text/gnugrep/default.nix
+++ b/pkgs/tools/text/gnugrep/default.nix
@@ -79,6 +79,11 @@ stdenv.mkDerivation {
     export MKDIR_P="mkdir -p"
   '';
 
+  configureFlags =
+    # Work around build failure caused by the gnulib workaround for
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114870. remove after GCC 15
+    lib.optional stdenv.hostPlatform.isCygwin "gl_cv_clean_version_stddef=yes";
+
   enableParallelBuilding = true;
 
   # Fix reference to sh in bootstrap-tools, and invoke grep via
@@ -92,7 +97,7 @@ stdenv.mkDerivation {
     chmod +x $out/bin/egrep $out/bin/fgrep
   '';
 
-  env = lib.optionalAttrs stdenv.hostPlatform.isMinGW {
+  env = lib.optionalAttrs (stdenv.hostPlatform.isMinGW || stdenv.hostPlatform.isCygwin) {
     NIX_CFLAGS_COMPILE = "-Wno-error=format-security";
   };