Fix build on newer compilers that need newer Eigen

Author: rpavlik

CMakeLists.txt

@@ -65,6 +65,7 @@ if(VPR20_FOUND OR VPR22_FOUND)
 endif()
 find_package(GMTL)
 find_package(OpenSceneGraph)
+find_package(Eigen3)
 
 set(Boost_USE_STATIC_LIBS ON)
 find_package(Boost COMPONENTS thread date_time chrono system)

third-party/CMakeLists.txt

@@ -5,9 +5,12 @@
 message(STATUS "")
 message(STATUS "Bundled third-party code:")
 
-message(STATUS "Using Eigen 3.2.2")
-list(APPEND THIRD_PARTY_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/eigen") # for Eigen
-
+if(Eigen3_FOUND)
+    list(APPEND THIRD_PARTY_INCLUDE_DIRS "${EIGEN3_INCLUDE_DIR}") # for Eigen
+else()
+    message(STATUS "Using Eigen 3.2.2")
+    list(APPEND THIRD_PARTY_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/eigen") # for Eigen
+endif()
 # Loki lib SVN https://loki-lib.svn.sourceforge.net/svnroot/loki-lib/trunk@1081
 message(STATUS "Using Loki template library r1081")
 list(APPEND THIRD_PARTY_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/loki-lib")