cpp-pinyin provides CMake targets:

  find_package(cpp-pinyin CONFIG REQUIRED)
  target_link_libraries(main PRIVATE cpp-pinyin::cpp-pinyin)

To use the library, you need to copy the dictionary files to the binary directory.

  add_custom_command(TARGET main POST_BUILD
      COMMAND "${CMAKE_COMMAND}" -E copy_directory
        "${cpp-pinyin_DIR}/dict"
        "$<TARGET_FILE_DIR:main>/dict"
  )