File Fix-Eigen3-version-search.patch of Package FreeCAD

commit 8547e798fb3b0f51953b18a2cb98f60aec0a7e33
Author: marioalexis <mario.passaglia@gmail.com>
Date:   Sat Sep 20 19:42:37 2025 -0300

    CMake: Fix Eigen3 version search

diff --git a/cMake/FindEigen3.cmake b/cMake/FindEigen3.cmake
index 57ee44be2a..ebddf5b6a1 100644
--- a/cMake/FindEigen3.cmake
+++ b/cMake/FindEigen3.cmake
@@ -23,16 +23,27 @@ if(NOT Eigen3_FIND_VERSION)
 endif(NOT Eigen3_FIND_VERSION)
 
 macro(_eigen3_check_version)
-  file(READ "${EIGEN3_INCLUDE_DIR}/Eigen/src/Core/util/Macros.h" _eigen3_version_header)
+  # file Version exists from Eigen3 5.0.0
+  if (EXISTS "${EIGEN3_INCLUDE_DIR}/Eigen/Version")
+    file(READ "${EIGEN3_INCLUDE_DIR}/Eigen/Version" _eigen3_version_header)
+    string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen3_major_version_match "${_eigen3_version_header}")
+    set(EIGEN3_MAJOR_VERSION "${CMAKE_MATCH_1}")
+    string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen3_minor_version_match "${_eigen3_version_header}")
+    set(EIGEN3_MINOR_VERSION "${CMAKE_MATCH_1}")
+    string(REGEX MATCH "define[ \t]+EIGEN_PATCH_VERSION[ \t]+([0-9]+)" _eigen3_patch_version_match "${_eigen3_version_header}")
+    set(EIGEN3_PATCH_VERSION "${CMAKE_MATCH_1}")
+    set(EIGEN3_VERSION ${EIGEN3_MAJOR_VERSION}.${EIGEN3_MINOR_VERSION}.${EIGEN3_PATCH_VERSION})
+  else()
+    file(READ "${EIGEN3_INCLUDE_DIR}/Eigen/src/Core/util/Macros.h" _eigen3_version_header)
+    string(REGEX MATCH "define[ \t]+EIGEN_WORLD_VERSION[ \t]+([0-9]+)" _eigen3_world_version_match "${_eigen3_version_header}")
+    set(EIGEN3_WORLD_VERSION "${CMAKE_MATCH_1}")
+    string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen3_major_version_match "${_eigen3_version_header}")
+    set(EIGEN3_MAJOR_VERSION "${CMAKE_MATCH_1}")
+    string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen3_minor_version_match "${_eigen3_version_header}")
+    set(EIGEN3_MINOR_VERSION "${CMAKE_MATCH_1}")
+    set(EIGEN3_VERSION ${EIGEN3_WORLD_VERSION}.${EIGEN3_MAJOR_VERSION}.${EIGEN3_MINOR_VERSION})
+  endif()
 
-  string(REGEX MATCH "define[ \t]+EIGEN_WORLD_VERSION[ \t]+([0-9]+)" _eigen3_world_version_match "${_eigen3_version_header}")
-  set(EIGEN3_WORLD_VERSION "${CMAKE_MATCH_1}")
-  string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen3_major_version_match "${_eigen3_version_header}")
-  set(EIGEN3_MAJOR_VERSION "${CMAKE_MATCH_1}")
-  string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen3_minor_version_match "${_eigen3_version_header}")
-  set(EIGEN3_MINOR_VERSION "${CMAKE_MATCH_1}")
-
-  set(EIGEN3_VERSION ${EIGEN3_WORLD_VERSION}.${EIGEN3_MAJOR_VERSION}.${EIGEN3_MINOR_VERSION})
   if(${EIGEN3_VERSION} VERSION_LESS ${Eigen3_FIND_VERSION})
     set(EIGEN3_VERSION_OK FALSE)
     message(STATUS "Eigen3 version ${EIGEN3_VERSION} found in ${EIGEN3_INCLUDE_DIR}, "