option('user_doc',
       type: 'boolean', value: true,
       description: 'Build and install docbook user documentation')

option('html_user_doc',
       type: 'boolean', value: true,
       description: 'Build and install HTML user documentation (requires xsltproc and stylesheets)')

option('tests',
       type: 'boolean', value: true,
       description: 'Build tests (requires nunit)')

option('run_tests',
       type: 'boolean', value: true,
       description: 'Whether to run tests (requires nunit-console)')