export only >3.0.1 cmake

Author: loriab

CMakeLists.txt

@@ -182,38 +182,42 @@ endif()
 include(GNUInstallDirs)
 include(CMakePackageConfigHelpers)
 
-# Build an interface library target:
-#   Though any project using pybind11 will need to include python headers and
-#   define c++11/14-ness, these are not included as interface includes or compile
-#   defs because (1) that's really the domain of the upstream project to decide,
-#   (2) we can get away with it since installation (headers) don't care about
-#   python version or C++ standard, and (3) this will make the easily target relocatable.
-add_library(pb11 INTERFACE)
-set_target_properties(pb11 PROPERTIES EXPORT_NAME "pybind11")
-target_include_directories(pb11 INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
-if(APPLE)
-    target_link_libraries(pb11 INTERFACE "-undefined dynamic_lookup")
+if(CMAKE_VERSION VERSION_GREATER 3.0.1)
+  # Build an interface library target:
+  #   Though any project using pybind11 will need to include python headers and
+  #   define c++11/14-ness, these are not included as interface includes or compile
+  #   defs because (1) that's really the domain of the upstream project to decide,
+  #   (2) we can get away with it since installation (headers) don't care about
+  #   python version or C++ standard, and (3) this will make the easily target relocatable.
+  add_library(pb11 INTERFACE)
+  set_target_properties(pb11 PROPERTIES EXPORT_NAME "pybind11")
+  target_include_directories(pb11 INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+  if(APPLE)
+      target_link_libraries(pb11 INTERFACE "-undefined dynamic_lookup")
+  endif()
 endif()
 
 if (PYBIND11_INSTALL)
   install(FILES ${PYBIND11_HEADERS}
           DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/pybind11)
-  install(TARGETS pb11
-          EXPORT "${PROJECT_NAME}Targets")
-
-      # explicit "share" not "DATADIR" for CMake search path
-  set(CMAKECONFIG_INSTALL_DIR "share/cmake/${PROJECT_NAME}")
-  configure_package_config_file(tools/${PROJECT_NAME}Config.cmake.in
-                                "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
-                                INSTALL_DESTINATION ${CMAKECONFIG_INSTALL_DIR})
-  write_basic_package_version_file(${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
-                                   VERSION 1.8
-                                   #VERSION ${${PROJECT_NAME}_VERSION}
-                                   COMPATIBILITY AnyNewerVersion)
-  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
-                ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
-          DESTINATION ${CMAKECONFIG_INSTALL_DIR})
-  install(EXPORT "${PROJECT_NAME}Targets"
-          NAMESPACE "${PROJECT_NAME}::"
-          DESTINATION ${CMAKECONFIG_INSTALL_DIR})
+  if(CMAKE_VERSION VERSION_GREATER 3.0.1)
+    install(TARGETS pb11
+            EXPORT "${PROJECT_NAME}Targets")
+
+        # explicit "share" not "DATADIR" for CMake search path
+    set(CMAKECONFIG_INSTALL_DIR "share/cmake/${PROJECT_NAME}")
+    configure_package_config_file(tools/${PROJECT_NAME}Config.cmake.in
+                                  "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
+                                  INSTALL_DESTINATION ${CMAKECONFIG_INSTALL_DIR})
+    write_basic_package_version_file(${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
+                                     VERSION 1.8
+                                     #VERSION ${${PROJECT_NAME}_VERSION}
+                                     COMPATIBILITY AnyNewerVersion)
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
+                  ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
+            DESTINATION ${CMAKECONFIG_INSTALL_DIR})
+    install(EXPORT "${PROJECT_NAME}Targets"
+            NAMESPACE "${PROJECT_NAME}::"
+            DESTINATION ${CMAKECONFIG_INSTALL_DIR})
+  endif()
 endif()