New -osirrox option sparse= controls extraction into sparse files

xorriso/opts_d_h.c

@@ -2308,6 +2308,7 @@ int Xorriso_option_help(struct XorrisO *xorriso, int flag)
 "           [:\"sort_lba_on\"|\"sort_lba_off\"]",
 "           [:\"strict_acl_on\"|\"strict_acl_off\"]",
 "           [:\"check_md5_on\"|\"check_md5_off\"|\"check_md5_force\"]",
+"           [:\"sparse=off\"|\"sparse=\"number]",
 "                 By default \"off\" the inverse operation of xorriso from ISO",
 "                 image to disk filesystem is disabled. \"on\" allows xorriso",
 "                 to create, overwrite, delete files in the disk filesystem.",