add XXX comments for unhandled errors
add XXX comments for unhandled errors

projedi/libzip,det/libzip,det/libzip,JanX2/libzip-git,JanX2/libzip-git,cysp/libzip,projedi/libzip,cysp/libzip,cysp/libzip,cysp/libzip,projedi/libzip,projedi/libzip,det/libzip,det/libzip