add / change BUILD_DEPENDS for all ports using camlp4.
Findlib is changed because it won't use camlp4 and doesn't install
the Bytes module anymore, which is now included in OCaml 4.02.
ok avsm@
need an upgrade, too.
* react uses opam without findlib as build system. Therefore call
ocamlbuild directly. And roll a custom do-install.
* lwt will need camlp4.
* zed has moved to github.
* utop, too.
* lambda-term, too. Also will it need camlp4.
OK jca@
Does not include the enhanced top-level, which will be added in a later update.
From Christopher Zimmermann <madroach@gmerlin.de>
--
Lwt provides very light-weight cooperative threads for OCaml;
``launching'' a thread is a very fast operation, it does not require
a new stack, a new process, or anything else. Moreover context
switches are very fast. In fact, it is so easy that a thread can
be launched for every system call. And composing cooperative threads
will allow highly asynchronous programs.
