for review: add mercury_opengl library

[Tyson Dowd]

On 16-Feb-1998, David Glen JEFFERY <dgj at cs.mu.OZ.AU> wrote:
> > 
> > % mercury_opengl -- a Mercury binding for OpenGL.
> > 
> > :- module mercury_opengl.
> > 
> > :- import_module mglu, mogl, mtogl.
> 
> You should probably have some kind of bugus declaration in here so that you
> don't get a warning about having nothing exported. Eg.
> 	:- type dont_get_a_warning.
> will do.

I've decided against this at the moment, because it's not really the
sort of bug we want to avoid (this is the documented way to create
a library at the moment!).

> 
> Hmmm... we really need some kind of package mechanism, don't we! :-)

Agreed, number one.