XmCreateOutline(3) on Linux
The text e5acecb12246, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
The Outline widget creation function "XmCreateOutline" "creation functions" "XmCreateOutline"