[Debian-med-packaging] Bug#739287: remove gzio from compilation

[tom fogal]

Mathieu Malaterre writes:
> Package: imagevis3d
> 
> gzio should not be compiled:

Hrm, actually I think that is required.

Potentially the confusion is over the name; 'gzio.c' is not gzip.  It's
actually just some code IV3D uses to interface with gzip.  It is used
when reading or writing compressed NRRD files, which are popular in
certain medical subdomains.

If the name is causing unforeseen problems with something, we can
probably change it.