First, build these C dependencies:
  glib-networking 2.28.6 (here)
  libsoup 2.34.1 (change sbo's version)
  webkit-gtk >= 1.4.0 (change sbo's version,
    remove --with-font-backend=pango from the ./configure call
    REMOVE IT! REMOVE IT! REMOVE IT! REMOVE IT! JUST FUCKING REMOVE IT!!!)
  NOTE: instead of getting libsoup 2.34.1 and glib-networking, you can use libsoup from rworkman's latest XFCE packages.

This whole folder is available as a tarball in ../slackbuilds.tar

Build these ocaml stuff in that order: all the tarballs on this server are the right versions even when I'm mentionning git.
  ocaml (3.12.1)
  ocaml-findlib (tarball from official website)
  ocaml-lablgtk (tarball here or adrien/mix git branch from http://git.ocamlcore.org/lablgtk/lablgtk.git)
  ocaml-lablwebkit (tarball here)
  ocaml-lablgtk-react (tarball here or master git branch from http://git.ocamlcore.org/lablgtk-react/lablgtk-react.git)

Do *NOT* build these:
  ocaml-react
  ocaml-lwt
Well, you could but they're not needed.
If you want to buidl them anyway, build ocaml-react *then* ocaml-lwt (and after the others).

Build caravel (do NOT use the slackbuild here):
  git clone http://git.ocamlcore.org/caravel/caravel.git
  cd caravel
  pmake configure
  pmake