pyhull should depend on qhull, not ship it

[JensTimmerman]

I already have qhull installed on our system,
so I used this patch to use the installed qhull, instead of building the one shipped with pyhull..
https://github.com/hpcugent/easybuild-easyconfigs/blob/0f709b5dccc6325285acd9624c88254d8b01ae92/easybuild/easyconfigs/p/pyhull/pyhull-1.5.4_use-provided-Qhull.patch

I prefer using my own qhull installation instead of using the one shipped with pyhull, because we also compile other python packages against qhull (e.g. matplotlib) and it is nicer to use the same version, and actually library, for each python package.

[shyuep]

Thanks for the suggestion. But as far as I know, to use system installed qhull requires a fair bit of rewrite and also, not everyone has qhull on their system.

Do you have a proposed method of implementing this?

[JensTimmerman]

You could make this optional,
but I do realise there isn't a simple solution for this, you could use pkg-resource to get the library paths, libraries and include paths, or a system like CMake, but indeed, none of them are a perfect solution.

For now, I've got it working with above patch and setting the correct environment variables, so other people looking to do this can at least find some info in this issue.