text: find_program(DOXYGEN doxygen)
  if (NOT DOXYGEN)
    message(STATUS "Target 'doc' disabled (requires doxygen)")
    return ()
  endif ()
  
  add_custom_target(doc
    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/build.py ${FMT_VERSION}
    SOURCES api.rst syntax.rst build.py conf.py _templates/layout.html)
  
  install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html/
          DESTINATION share/doc/fmt OPTIONAL)
  