NEW: lang/ocaml-camlp5

Hi ports --

Attached is a new port, lang/ocaml-camlp5. Camlp5 is an OCaml
Preprocessor and Pretty-Printer.
A quick perusal of the archives indicates that this piece of software
has been proposed numerous times, as far back as 2010, yet has never
been imported. The archives are scarce on reasons why it wasn't ever
imported, but it seems like it has something to do with math/coq.
Looking at Coq, the latest version says that Camlp4 no longer works,
only Camlp5. And Camlp5 doesn't conflict with Camlp4, so let's say we're
future-proofing for whenever someone comes along who wants to update
math/coq.

---
pkg/DESCR:
Camlp5 is a preprocessor and pretty-printer for OCaml programs. It also
provides parsing and printing tools.

As a preprocessor, it allows one to:
* extend the syntax of OCaml,
* redefine the whole syntax of the language.

As a pretty printer, it allows one to:
* display OCaml programs in an elegant way,
* convert from one syntax to another,
* check the results of syntax extensions.

Camlp5 also provides some parsing and pretty printing tools:
* extensible grammars
* extensible printers
* stream parsers and lexers
* pretty print module

It works as a shell command and can also be used in the OCaml toplevel.
---

Run tested on amd64 and build tested on armv7. But as this is the first
time I'm working with OCaml, more experienced eyes appreciated.

OK?

~Brian