From a61e4dbb180c7dabcc932ac03fc6d4d724b9178e Mon Sep 17 00:00:00 2001
From: David McFarland <corngood@gmail.com>
Date: Mon, 29 Dec 2025 14:53:21 -0400
Subject: [PATCH] cygwin-dll-link: move from make-derivation to cross stdenv

---
 .../cygwin/cygwin-dll-link-hook}/cygwin-dll-link.sh |  2 +-
 .../cygwin/cygwin-dll-link-hook/default.nix         | 13 +++++++++++++
 pkgs/os-specific/cygwin/default.nix                 |  2 ++
 pkgs/stdenv/cross/default.nix                       |  5 ++++-
 pkgs/stdenv/generic/make-derivation.nix             |  1 -
 5 files changed, 20 insertions(+), 3 deletions(-)
 rename pkgs/{build-support/setup-hooks => os-specific/cygwin/cygwin-dll-link-hook}/cygwin-dll-link.sh (98%)
 create mode 100644 pkgs/os-specific/cygwin/cygwin-dll-link-hook/default.nix

diff --git a/pkgs/build-support/setup-hooks/cygwin-dll-link.sh b/pkgs/os-specific/cygwin/cygwin-dll-link-hook/cygwin-dll-link.sh
similarity index 98%
rename from pkgs/build-support/setup-hooks/cygwin-dll-link.sh
rename to pkgs/os-specific/cygwin/cygwin-dll-link-hook/cygwin-dll-link.sh
index a9309925e658..371ba633edc8 100644
--- a/pkgs/build-support/setup-hooks/cygwin-dll-link.sh
+++ b/pkgs/os-specific/cygwin/cygwin-dll-link-hook/cygwin-dll-link.sh
@@ -18,7 +18,7 @@ addOutputDLLPaths() {
 postInstallHooks+=(addOutputDLLPaths)
 
 _dllDeps() {
-  "$OBJDUMP" -p "$1" \
+  @objdump@ -p "$1" \
     | sed -n 's/.*DLL Name: \(.*\)/\1/p' \
     | sort -u
 }
diff --git a/pkgs/os-specific/cygwin/cygwin-dll-link-hook/default.nix b/pkgs/os-specific/cygwin/cygwin-dll-link-hook/default.nix
new file mode 100644
index 000000000000..b3185140f2ea
--- /dev/null
+++ b/pkgs/os-specific/cygwin/cygwin-dll-link-hook/default.nix
@@ -0,0 +1,13 @@
+{
+  lib,
+  makeSetupHook,
+  binutils-unwrapped,
+  stdenv,
+  callPackage,
+}:
+makeSetupHook {
+  name = "cygwin-dll-link-hook";
+  substitutions = {
+    objdump = "${lib.getBin binutils-unwrapped}/${stdenv.targetPlatform.config}/bin/objdump";
+  };
+} ./cygwin-dll-link.sh
diff --git a/pkgs/os-specific/cygwin/default.nix b/pkgs/os-specific/cygwin/default.nix
index 09f69ff9f9b2..d1217f7880c1 100644
--- a/pkgs/os-specific/cygwin/default.nix
+++ b/pkgs/os-specific/cygwin/default.nix
@@ -21,5 +21,7 @@ makeScopeWithSplicing' {
       # this is here to avoid symlinks being made to cygwin1.dll in /nix/store
       newlib-cygwin-nobin = callPackage ./newlib-cygwin/nobin.nix { };
       newlib-cygwin-headers = callPackage ./newlib-cygwin { headersOnly = true; };
+
+      cygwinDllLinkHook = callPackage ./cygwin-dll-link-hook { };
     };
 }
diff --git a/pkgs/stdenv/cross/default.nix b/pkgs/stdenv/cross/default.nix
index cc53957eee0d..b194c780a319 100644
--- a/pkgs/stdenv/cross/default.nix
+++ b/pkgs/stdenv/cross/default.nix
@@ -83,7 +83,10 @@ lib.init bootStages
                   || p.isGenode;
               in
               f hostPlatform && !(f buildPlatform)
-            ) buildPackages.updateAutotoolsGnuConfigScriptsHook;
+            ) buildPackages.updateAutotoolsGnuConfigScriptsHook
+            ++ lib.optional (
+              hostPlatform.isCygwin && !buildPlatform.isCygwin
+            ) buildPackages.cygwin.cygwinDllLinkHook;
         })
       );
     in
diff --git a/pkgs/stdenv/generic/make-derivation.nix b/pkgs/stdenv/generic/make-derivation.nix
index cdfeb34a2411..d66fbf71035e 100644
--- a/pkgs/stdenv/generic/make-derivation.nix
+++ b/pkgs/stdenv/generic/make-derivation.nix
@@ -475,7 +475,6 @@ let
           nativeBuildInputs
           ++ optional separateDebugInfo' ../../build-support/setup-hooks/separate-debug-info.sh
           ++ optional isWindows ../../build-support/setup-hooks/win-dll-link.sh
-          ++ optional isCygwin ../../build-support/setup-hooks/cygwin-dll-link.sh
           ++ optionals doCheck nativeCheckInputs
           ++ optionals doInstallCheck nativeInstallCheckInputs;