option('version-tag', type : 'string',
description : 'override the git version string')
+option('mode', type : 'combo', choices : ['default', 'developer'],
+ description : 'enable additional checks suitable for systemd development')
+
option('split-usr', type : 'combo', choices : ['auto', 'true', 'false'],
description : '''/bin, /sbin aren't symlinks into /usr''')
option('split-bin', type : 'combo', choices : ['auto', 'true', 'false'],