CMake: Improvements from kitware

• Add multiple CMake option to control which parts of CDI should be built
• Add installation of the cdilib and associated CMake config file
• Fix some issues with linking
• Fix some issues in cdi-config.cmake

src/CMakeLists.txt

@@ -190,17 +190,44 @@ list( APPEND cdi_unknown
   resource_unpack.h
 )
 
+option(CDI_BUILD_UNKNOWN "Build unknown sources in libcdi" ON)
+mark_as_advanced(CDI_BUILD_UNKNOWN)
+if (CDI_BUILD_UNKNOWN)
+  list(APPEND cdi_src_files ${cdi_unknown})
+endif ()
+
 # Support exporting all symbolds on Windows
 set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
 
 add_library(cdilib
-  ${cdi_src_files} ${cdi_unknown}
+  ${cdi_src_files}
 #  INSTALL_HEADERS_LIST  cdi.h
 )
 
 target_include_directories(cdilib PRIVATE "${PROJECT_BINARY_DIR}/src/config.h")
-target_link_libraries(cdilib eccodes netCDF::netcdf)
+target_link_libraries(cdilib ${cdi_linked_libs})
 target_compile_definitions(cdilib PRIVATE PACKAGE_NAME="${PROJECT_NAME}" VERSION="${CMAKE_PROJECT_VERSION}" ${cdi_compile_defs})
 
 add_library(cdilib::cdilib ALIAS cdilib)
 
+include(GNUInstallDirs)
+install(FILES cdi.h calendar.h cdi_datetime.h julian_date.h DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
+install(TARGETS cdilib
+  ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+  LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}")
+
+include(CMakePackageConfigHelpers)
+configure_package_config_file(
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/cdi/cdi-config.cmake.in" "${CMAKE_BINARY_DIR}/cmake/cdi-config.cmake"
+  INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/cdi")
+write_basic_package_version_file(
+  "${CMAKE_BINARY_DIR}/cmake/cdi-config-version.cmake"
+  VERSION "${PACKAGE_VERSION}"
+  COMPATIBILITY SameMajorVersion)
+install(
+  FILES
+    "${CMAKE_BINARY_DIR}/cmake/cdi-config.cmake"
+    "${CMAKE_BINARY_DIR}/cmake/cdi-config-version.cmake"
+  DESTINATION
+    "${CMAKE_INSTALL_LIBDIR}/cmake/cdi")