Bug#978017: opencascade: please, make dependency on libvtk7 optional

[Kurt Kremitzki]

Hello Daniel,

On Thursday, December 24, 2020 7:43:47 AM CST you wrote:
> Source: opencascade
> Version: 7.5.0+dfsg1-2
> Severity: wishlist
> 
> Dear maintainer,
> 
> Most applications depending on libocct-* libraries do not need the Vtk visualization
> (for example Kicad) and Vtk adds about 220MB of extra disk space.
> 
> It would be great if the dependency to Vtk could be made optional (or a recomends), so
> that users that does not need the visuzalization can omit it.
> 
> Regards,
> 
>     Daniel.
> 

Indeed I see that libocct-data-exchange-dev, the dependency KiCad uses, has 
increased its install size on a base system +550 MB due to this dependency, 
even pulling in MySQL now. I will revert it with the next upload until a 
better solution can be found