Merge pull request #71 from gergondet/topic/ImproveEigenDetection

[cmake] Improve Eigen detection

CMakeLists.txt

@@ -28,7 +28,12 @@ PROJECT(${PROJECT_NAME} ${PROJECT_ARGS})
 CHECK_MINIMAL_CXX_STANDARD(11 ENFORCE)
 
 # Project dependencies
-ADD_PROJECT_DEPENDENCY(Eigen3 REQUIRED PKG_CONFIG_REQUIRES eigen3)
+FIND_PACKAGE(Eigen3 QUIET NO_CMAKE_PACKAGE_REGISTRY)
+IF(Eigen3_FOUND)
+  ADD_PROJECT_DEPENDENCY(Eigen3 REQUIRED NO_CMAKE_PACKAGE_REGISTRY PKG_CONFIG_REQUIRES eigen3)
+ELSE(Eigen3_FOUND)
+  ADD_PROJECT_DEPENDENCY(Eigen3 MODULE REQUIRED PKG_CONFIG_REQUIRES eigen3)
+ENDIF(Eigen3_FOUND)
 FIND_PACKAGE(pinocchio QUIET)
 OPTION(CURVES_WITH_PINOCCHIO_SUPPORT "Build with pinocchio support" ${pinocchio_FOUND})
 IF(CURVES_WITH_PINOCCHIO_SUPPORT)
@@ -82,7 +87,11 @@ SET(${PROJECT_NAME}_HEADERS
   )
 
 ADD_LIBRARY(${PROJECT_NAME} INTERFACE)
-TARGET_INCLUDE_DIRECTORIES(${PROJECT_NAME} SYSTEM INTERFACE ${EIGEN3_INCLUDE_DIR})
+IF(TARGET Eigen3::Eigen)
+  TARGET_LINK_LIBRARIES(${PROJECT_NAME} INTERFACE Eigen3::Eigen)
+ELSE(TARGET Eigen3::Eigen)
+  TARGET_INCLUDE_DIRECTORIES(${PROJECT_NAME} SYSTEM INTERFACE ${EIGEN3_INCLUDE_DIR})
+ENDIF(TARGET Eigen3::Eigen)
 TARGET_INCLUDE_DIRECTORIES(${PROJECT_NAME} INTERFACE $<INSTALL_INTERFACE:include>)
 TARGET_LINK_LIBRARIES(${PROJECT_NAME} INTERFACE Boost::serialization)
 IF(CURVES_WITH_PINOCCHIO_SUPPORT)