export(TARGETS <target>... [NAMESPACE <namespace>]
  [APPEND] FILE <filename> [EXPORT_LINK_INTERFACE_LIBRARIES]
[CXX_MODULES_DIRECTORY <directory>])
export(EXPORT <export-name> [NAMESPACE <namespace>] [FILE <filename>]
  [CXX_MODULES_DIRECTORY <directory>] [EXPORT_PACKAGE_DEPENDENCIES])
export(EXPORT <export-name> PACKAGE_INFO <package-name>
  [PROJECT <project-name>|NO_PROJECT_METADATA]
  [APPENDIX <appendix-name>]
  [LOWER_CASE_FILE]
  [VERSION <version>
  [COMPAT_VERSION <version>]
  [VERSION_SCHEMA <string>]]
  [DEFAULT_TARGETS <target>...]
  [DEFAULT_CONFIGURATIONS <config>...]
  [DESCRIPTION <project-description-string>]
[HOMEPAGE_URL <url-string>])
export(PACKAGE <PackageName>)
export(SETUP <export-name>
  [PACKAGE_DEPENDENCY <dep>
  [ENABLED (<bool-true>|<bool-false>|AUTO)]
  [EXTRA_ARGS <args>...]
  ] [...]
  [TARGET <target>
  [XCFRAMEWORK_LOCATION <location>]
  ] [...]
)