spectra.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8801572..a4ab77b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,9 +21,11 @@ include(FeatureSummary) # More verbose Output for libraries using set_package_pr
 
 # Look for supporting libraries
 # -----------------------------
-find_package(Eigen3 NO_MODULE REQUIRED)
-set_package_properties(Eigen3 PROPERTIES TYPE REQUIRED PURPOSE "C++ vector data structures")
-message(STATUS "Found Eigen3 Version: ${Eigen3_VERSION} Path: ${Eigen3_DIR}")
+if(NOT TARGET Eigen3::Eigen)
+  findjpackage(Eigen3 NO_MODULE REQUIRED)
+  set_package_properties(Eigen3 PROPERTIES TYPE REQUIRED PURPOSE "C++ vector data structures")
+  message(STATUS "Found Eigen3 Version: ${Eigen3_VERSION} Path: ${Eigen3_DIR}")
+endif()
 
 # Setup library
 # -------------