rxvt binary package in Ubuntu Xenial s390x

 Rxvt is an 8-bit clean, color xterm replacement that uses significantly
 less memory than a conventional xterm, mostly since it doesn't support
 toolkit configurability or Tek graphics, but also since features can
 be removed at compile-time to reflect your needs.
 .
 The distribution also includes rclock, the smaller/better xclock
 replacement with appointment scheduling and xbiff functionality.

Source package