From f0cae1e3c684960a590f6cc5feb2285c467f9f76 Mon Sep 17 00:00:00 2001
From: Ben Darwin <bcdarwin@gmail.com>
Date: Mon, 16 Dec 2024 22:11:51 -0500
Subject: [PATCH] itk: fix contradictory ITK_USE_SYSTEM_EIGEN cmake flags

---
 pkgs/development/libraries/itk/generic.nix | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pkgs/development/libraries/itk/generic.nix b/pkgs/development/libraries/itk/generic.nix
index b569c84e4ed61..383baaabc1940 100644
--- a/pkgs/development/libraries/itk/generic.nix
+++ b/pkgs/development/libraries/itk/generic.nix
@@ -115,8 +115,7 @@ stdenv.mkDerivation {
       "-DBUILD_SHARED_LIBS=ON"
       "-DITK_FORBID_DOWNLOADS=ON"
       "-DITK_USE_SYSTEM_LIBRARIES=ON" # finds common libraries e.g. hdf5, libpng, libtiff, zlib, but not GDCM, NIFTI, MINC, etc.
-      "-DITK_USE_SYSTEM_EIGEN=ON"
-      "-DITK_USE_SYSTEM_EIGEN=OFF"
+      (lib.cmakeBool "ITK_USE_SYSTEM_EIGEN" (lib.versionAtLeast version "5.4"))
       "-DITK_USE_SYSTEM_GOOGLETEST=OFF" # ANTs build failure due to https://github.com/ANTsX/ANTs/issues/1489
       "-DITK_USE_SYSTEM_GDCM=ON"
       "-DITK_USE_SYSTEM_MINC=ON"
@@ -152,10 +151,10 @@ stdenv.mkDerivation {
 
   buildInputs =
     [
-      eigen
       libX11
       libuuid
     ]
+    ++ lib.optionals (lib.versionAtLeast version "5.4") [ eigen ]
     ++ lib.optionals stdenv.hostPlatform.isDarwin [ Cocoa ]
     ++ lib.optionals enablePython [ python ]
     ++ lib.optionals withVtk [ vtk ];