llvm-project/libcxx/include/CMakeLists.txt

if (NOT LIBCXX_INSTALL_SUPPORT_HEADERS)
  set(LIBCXX_SUPPORT_HEADER_PATTERN PATTERN "support" EXCLUDE)
endif()

if (LIBCXX_NEEDS_SITE_CONFIG)
  # Generate a custom __config header. The new header is created
  # by prepending __config_site to the current __config header.
  add_custom_command(OUTPUT ${LIBCXX_BINARY_DIR}/__generated_config
    COMMAND ${PYTHON_EXECUTABLE} ${LIBCXX_SOURCE_DIR}/utils/cat_files.py
      ${LIBCXX_BINARY_DIR}/__config_site
      ${LIBCXX_SOURCE_DIR}/include/__config
      -o ${LIBCXX_BINARY_DIR}/__generated_config
    DEPENDS ${LIBCXX_SOURCE_DIR}/include/__config
            ${LIBCXX_BINARY_DIR}/__config_site
  )
  # Add a target that executes the generation commands.
  add_custom_target(generate_config_header ALL
    DEPENDS ${LIBCXX_BINARY_DIR}/__generated_config)
  set(generated_config_deps generate_config_header)
endif()

set(LIBCXX_HEADER_PATTERN
  PATTERN "*"
  PATTERN "CMakeLists.txt" EXCLUDE
  PATTERN ".svn" EXCLUDE
  PATTERN "__config_site.in" EXCLUDE
  ${LIBCXX_SUPPORT_HEADER_PATTERN}
  )

if(NOT LIBCXX_USING_INSTALLED_LLVM AND LLVM_BINARY_DIR)
  file(COPY .
    DESTINATION "${LLVM_BINARY_DIR}/include/c++/v1"
    FILES_MATCHING
    ${LIBCXX_HEADER_PATTERN}
    )

  if (LIBCXX_NEEDS_SITE_CONFIG)
    # Copy the generated header as __config into build directory.
    add_custom_command(
        TARGET generate_config_header POST_BUILD
        COMMAND ${CMAKE_COMMAND} -E copy
                ${LIBCXX_BINARY_DIR}/__generated_config
                ${LLVM_BINARY_DIR}/include/c++/v1/__config)
  endif()
endif()

if (LIBCXX_INSTALL_HEADERS)
  install(DIRECTORY .
    DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1
    COMPONENT cxx-headers
    FILES_MATCHING
    ${LIBCXX_HEADER_PATTERN}
    PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
  )

  if (LIBCXX_NEEDS_SITE_CONFIG)
    # Install the generated header as __config.
    install(FILES ${LIBCXX_BINARY_DIR}/__generated_config
      DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1
      PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
      RENAME __config
      COMPONENT cxx-headers)
  endif()

  if (NOT CMAKE_CONFIGURATION_TYPES)
    # this target is just needed as a placeholder for the distribution target
    add_custom_target(cxx-headers)
    add_custom_target(install-cxx-headers
                      DEPENDS cxx-headers ${generated_config_deps}
                      COMMAND "${CMAKE_COMMAND}"
                              -DCMAKE_INSTALL_COMPONENT=cxx-headers
                              -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
    # Stripping is a no-op for headers
    add_custom_target(install-cxx-headers-stripped DEPENDS install-cxx-headers)

    add_custom_target(libcxx-headers)
    add_custom_target(install-libcxx-headers DEPENDS install-cxx-headers)
    add_custom_target(install-libcxx-headers-stripped DEPENDS install-cxx-headers-stripped)
  endif()
endif()