option('enable_png',
       description: 'Enable PNG loader (requires libpng)',
       type: 'boolean',
       value: true)
option('enable_tiff',
       description: 'Enable TIFF loader (requires libtiff)',
       type: 'boolean',
       value: true)
option('enable_jpeg',
       description: 'Enable JPEG loader (requires libjpeg)',
       type: 'boolean',
       value: true)
option('enable_jasper',
       description: 'Enable JPEG2000 loader (requires libjasper)',
       type: 'boolean',
       value: true)
option('builtin_loaders',
       description: 'Comma-separated list of loaders to build into gdk-pixbuf',
       type: 'string',
       value: 'none')