testing/jackline: new aport
Jackline is a minimalistic console XMPP (Jabber) client written in OCaml.
It uses XMPP, TLS, and OTR libraries that are written completely in OCaml, and so it aims to be a secure alternative to clients utilizing loudmouth, libpurple, and so on.
This MR contains all the dependencies needed to build Jackline. Even though the final executable links only to musl-libc, libev, and libgmp, the various OCaml libraries will be useful for other software.