diff '--color=auto' -ur onnxruntime-1.31.0.orig/cmake/external/onnxruntime_external_deps.cmake onnxruntime-1.31.0/cmake/external/onnxruntime_external_deps.cmake
--- onnxruntime-1.31.0.orig/cmake/external/onnxruntime_external_deps.cmake	2026-10-09 16:59:56.004073932 +0200
+++ onnxruntime-1.31.0/cmake/external/onnxruntime_external_deps.cmake	2026-10-09 17:01:15.474595280 +0200
@@ -586,7 +586,7 @@
                  "protobuf version: ${Protobuf_VERSION}")
 endif()
 
-if(onnxruntime_USE_VCPKG)
+if(onnxruntime_USE_PREINSTALLED_EIGEN)
   find_package(Eigen3 CONFIG REQUIRED)
 else()
   include(external/eigen.cmake)