diff --git a/Eigen/src/LU/CMakeLists.txt b/Eigen/src/LU/CMakeLists.txt
index 2788595b0..e0d8d78c1 100644
--- a/Eigen/src/LU/CMakeLists.txt
+++ b/Eigen/src/LU/CMakeLists.txt
@@ -4,3 +4,5 @@ INSTALL(FILES
   ${Eigen_LU_SRCS}
   DESTINATION ${INCLUDE_INSTALL_DIR}/Eigen/src/LU COMPONENT Devel
   )
+
+ADD_SUBDIRECTORY(arch)