fix compatibility with find package

CMakeLists.txt

@@ -65,40 +65,67 @@ if(CXXOPTS_USE_UNICODE_HELP)
     target_compile_definitions(cxxopts INTERFACE CXXOPTS_USE_UNICODE)
 endif()
 
-target_include_directories(cxxopts INTERFACE
-    $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
-    $<INSTALL_INTERFACE:include>
+set(PROJECT_PREFIX ${PROJECT_NAME}-${${PROJECT_NAME}_VERSION})
+
+target_include_directories(cxxopts
+    INTERFACE
+        $<BUILD_INTERFACE:${${PROJECT_NAME}_SOURCE_DIR}/include>
+        $<INSTALL_INTERFACE:include/${PROJECT_PREFIX}>
     )
 
+set(install_runtime_dir ${CMAKE_INSTALL_BINDIR})
+set(install_config_dir  ${CMAKE_INSTALL_LIBDIR}/${PROJECT_PREFIX}/cmake)
+set(install_library_dir ${CMAKE_INSTALL_LIBDIR}/${PROJECT_PREFIX}/${CMAKE_BUILD_TYPE})
+set(install_archive_dir ${CMAKE_INSTALL_LIBDIR}/${PROJECT_PREFIX}/${CMAKE_BUILD_TYPE}/static)
+set(install_include_dir ${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_PREFIX}/${PROJECT_NAME})
+
 include(CMakePackageConfigHelpers)
 set(CXXOPTS_CMAKE_DIR "lib/cmake/cxxopts" CACHE STRING
   "Installation directory for cmake files, relative to ${CMAKE_INSTALL_PREFIX}.")
-set(version_config "${PROJECT_BINARY_DIR}/cxxopts-config-version.cmake")
-set(project_config "${PROJECT_BINARY_DIR}/cxxopts-config.cmake")
-set(targets_export_name cxxopts-targets)
+set(version_config "${PROJECT_BINARY_DIR}/${PROJECT_NAME}-config-version.cmake")
+set(project_config "${PROJECT_BINARY_DIR}/${PROJECT_NAME}-config.cmake")
+set(targets_export_name ${PROJECT_NAME}-targets)
 
 # Generate the version, config and target files into the build directory.
 write_basic_package_version_file(
     ${version_config}
     VERSION ${VERSION}
     COMPATIBILITY AnyNewerVersion)
 configure_package_config_file(
-    ${PROJECT_SOURCE_DIR}/cxxopts-config.cmake.in
-    ${project_config}
-    INSTALL_DESTINATION ${CXXOPTS_CMAKE_DIR})
-export(TARGETS cxxopts NAMESPACE cxxopts::
-    FILE ${PROJECT_BINARY_DIR}/${targets_export_name}.cmake)
+  ${PROJECT_NAME}-config.cmake.in
+  ${project_config}
+  INSTALL_DESTINATION ${install_config_dir})
+
+install(TARGETS ${PROJECT_NAME}
+  EXPORT ${PROJECT_NAME}-targets
+  RUNTIME DESTINATION ${install_runtime_dir}
+  LIBRARY DESTINATION ${install_library_dir}
+  ARCHIVE DESTINATION ${install_archive_dir})
+
+install(EXPORT ${PROJECT_NAME}-targets
+  FILE ${PROJECT_NAME}-targets.cmake
+  NAMESPACE ${PROJECT_NAME}::
+  DESTINATION ${install_config_dir})
+
+export(EXPORT ${PROJECT_NAME}-targets
+  FILE ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}-targets.cmake
+  NAMESPACE ${PROJECT_NAME}::)
+
+export(PACKAGE ${PROJECT_NAME})
 
 # Install version, config and target files.
 install(
     FILES ${project_config} ${version_config}
     DESTINATION ${CXXOPTS_CMAKE_DIR})
-install(EXPORT ${targets_export_name} DESTINATION ${CXXOPTS_CMAKE_DIR}
+install(
+    EXPORT ${targets_export_name}
+    DESTINATION ${CXXOPTS_CMAKE_DIR}
     NAMESPACE cxxopts::)
 
-# Install the header file and export the target
-install(TARGETS cxxopts EXPORT ${targets_export_name} DESTINATION lib)
-install(FILES ${PROJECT_SOURCE_DIR}/include/cxxopts.hpp DESTINATION include)
+# Install the header file
+install(
+  FILES ${PROJECT_SOURCE_DIR}/include/cxxopts.hpp
+  DESTINATION ${install_include_dir})
 
 add_subdirectory(src)
 add_subdirectory(test)

cxxopts-config.cmake.in

@@ -1,4 +1,6 @@
 @PACKAGE_INIT@
 
-include(${CMAKE_CURRENT_LIST_DIR}/@[email protected])
+if(NOT TARGET cxxopts::cxxopts)
+    include(${CMAKE_CURRENT_LIST_DIR}/@[email protected])
+endif()
 check_required_components(cxxopts)