option('runtime', type : 'combo',
  choices : ['libidn2', 'libicu', 'libidn', 'no', 'auto'], value : 'auto',
  description : 'Specify the IDNA library used for libpsl run-time conversions')

option('builtin', type : 'combo',
  choices : ['libidn2', 'libicu', 'libidn', 'no', 'auto'], value : 'auto',
  description : 'Specify the IDNA library used for built-in data generation')

option('psl_distfile', type : 'string', value : '',
  description : 'path to distribution-wide PSL file')

option('psl_file', type : 'string', value : '',
  description : 'path to PSL file')

option('psl_testfile', type : 'string', value : '',
  description : 'path to PSL test file')