description: 'use specified string as sub-version of the package')
option('smbd', type : 'string', value : '',
description: 'Path to smbd for slirp networking')
-option('sphinx_build', type : 'string', value : '',
+option('sphinx_build', type : 'string', value : 'sphinx-build',
description: 'Use specified sphinx-build for building document')
option('iasl', type : 'string', value : '',
description: 'Path to ACPI disassembler')