option('libraw', type : 'feature', value : 'auto',
    description : 'Build with RAW support, requires LibRaw')
option('librsvg', type : 'feature', value : 'auto',
	description : 'Build with SVG support, requires librsvg')
option('gdk-pixbuf', type : 'feature', value : 'auto',
	description : 'Build with a fallback to the gdk-pixbuf library')