cmake: refactor exported CMake configuration

- Avoid relative paths (../../..) in exported CMake variables
- Find dependencies in downstream packages and do not export build-time include
  directories
- Use find_package(Eigen3) CMake config shipped with newer Eigen versions and
  install custom FindEigen3.cmake to find older versions
- Rename CMake templates to match the installed filenames

orocos_kdl/CMakeLists.txt

@@ -45,13 +45,12 @@ ENDIF ( NOT CMAKE_BUILD_TYPE )
 
 SET( KDL_CFLAGS "")
 
-find_package(Eigen 3 QUIET)
-if(NOT Eigen_FOUND)
+find_package(Eigen3 QUIET)
+if(NOT EIGEN3_FOUND)
   include(${PROJ_SOURCE_DIR}/cmake/FindEigen3.cmake)
-  set(Eigen_INCLUDE_DIR "${EIGEN3_INCLUDE_DIR}")
 endif()
-include_directories(${Eigen_INCLUDE_DIR})
-SET(KDL_CFLAGS "${KDL_CFLAGS} -I${Eigen_INCLUDE_DIR}")
+include_directories(${EIGEN3_INCLUDE_DIR})
+SET(KDL_CFLAGS "${KDL_CFLAGS} -I${EIGEN3_INCLUDE_DIR}")
 
 # Check the platform STL containers capabilities
 include(cmake/CheckSTLContainers.cmake)
@@ -110,11 +109,12 @@ export(TARGETS orocos-kdl
 export(PACKAGE orocos_kdl)
 
 # Generate CMake package configuration
-CONFIGURE_FILE(KDLConfig.cmake.in
+CONFIGURE_FILE(orocos_kdl-config.cmake.in
   ${PROJECT_BINARY_DIR}/orocos_kdl-config.cmake @ONLY)
-CONFIGURE_FILE(KDLConfigVersion.cmake.in
+CONFIGURE_FILE(orocos_kdl-config-version.cmake.in
   ${PROJECT_BINARY_DIR}/orocos_kdl-config-version.cmake @ONLY)
 
+INSTALL(FILES cmake/FindEigen3.cmake DESTINATION share/orocos_kdl/cmake)
 INSTALL(FILES ${PROJECT_BINARY_DIR}/orocos_kdl-config.cmake DESTINATION share/orocos_kdl/cmake)
 INSTALL(FILES ${PROJECT_BINARY_DIR}/orocos_kdl-config-version.cmake DESTINATION share/orocos_kdl/cmake)
 INSTALL(EXPORT OrocosKDLTargets DESTINATION share/orocos_kdl/cmake)

orocos_kdl/KDLConfig.cmake.in → orocos_kdl/orocos_kdl-config.cmake.in

@@ -4,14 +4,22 @@
 #  orocos_kdl_LIBRARIES    - libraries to link against for Orocos KDL
 #  orocos_kdl_PKGCONFIG_DIR - directory containing the .pc pkgconfig files
 
+# Find dependencies
+find_package(Boost REQUIRED)
+find_package(Eigen3 QUIET)
+if(NOT EIGEN3_FOUND)
+  include(${CMAKE_CURRENT_LIST_DIR}/FindEigen3.cmake)
+endif()
+
 # Compute paths
-set(orocos_kdl_INCLUDE_DIRS "${CMAKE_CURRENT_LIST_DIR}/../../../include;@Boost_INCLUDE_DIRS@;@Eigen_INCLUDE_DIR@")
+get_filename_component(orocos_kdl_PREFIX "${CMAKE_CURRENT_LIST_DIR}/../../.." ABSOLUTE)
 
 if(NOT TARGET orocos-kdl)
   include("${CMAKE_CURRENT_LIST_DIR}/OrocosKDLTargets.cmake")
 endif()
 
+set(orocos_kdl_INCLUDE_DIRS "${orocos_kdl_PREFIX}/include;${Boost_INCLUDE_DIRS};${EIGEN3_INCLUDE_DIR}")
 set(orocos_kdl_LIBRARIES orocos-kdl)
 
 # where the .pc pkgconfig files are installed
-set(orocos_kdl_PKGCONFIG_DIR "${CMAKE_CURRENT_LIST_DIR}/../../../lib/pkgconfig")
+set(orocos_kdl_PKGCONFIG_DIR "${orocos_kdl_PREFIX}/lib/pkgconfig")