replaced_by multiple ports?

[Jeremy Lavergne]

> I would like to split an existing port (healpix) into two or more new ports (healpix-c, healpix-cxx). Is there a way to accomplish this with replaced_by, or are there any examples of ports for which something similar has happened in the past?

I believe replaced-by only handles a one-to-one replacement.

I'd recommend making healpix a virtual package (no real contents, just one file in to place into a ${prefix}/share/doc/${name}/) that depends on both healpix-c and healpix-cxx. 

You could add a `notes` message indicating healpix no longer does anything: users can set healpix-c[xx] as requested and then uninstall healpix.