Compiling VTK for POWER (ppc64le) PC

Hi!

I would like to compile VTK with the Python wrapping for linux-ppc64le running RHEL 7.4. Specifically for an AC922, which contains an IBM POWER9 PC, and 4*V100 Nvidia GPUs.

I know that VTK-m has been [built successfully for the architecture](https://developer.download.nvidia.com/video/gputechconf/gtc/2019/presentation/s9458-vtk-m-lessons-from-building-a-visualization-toolkit-for-massively-threaded-architectures-v2.pdf), but I'm not sure that provides a Python wrapper.

Could anyone provide any direction/pointers on how to compile for linux-ppc64le?

```
$ conda info
active environment : vtk_python
active env location : /home/tom/anaconda3/envs/vtk_python
shell level : 2
user config file : /home/tom/.condarc
populated config files : /home/tom/.condarc
conda version : 4.7.5
conda-build version : not installed
python version : 3.7.2.final.0
virtual packages : __cuda=10.1
base environment : /home/tom/anaconda3 (writable)
channel URLs : https://public.dhe.ibm.com/ibmdl/export/pub/software/server/ibm-ai/conda/linux-ppc64le
https://public.dhe.ibm.com/ibmdl/export/pub/software/server/ibm-ai/conda/noarch
https://conda.anaconda.org/conda-forge/linux-ppc64le
https://conda.anaconda.org/conda-forge/noarch
https://repo.anaconda.com/pkgs/main/linux-ppc64le
https://repo.anaconda.com/pkgs/main/noarch
https://repo.anaconda.com/pkgs/r/linux-ppc64le
https://repo.anaconda.com/pkgs/r/noarch
package cache : /home/tom/anaconda3/pkgs
/home/tom/.conda/pkgs
envs directories : /home/tom/anaconda3/envs
/home/tom/.conda/envs
platform : linux-ppc64le
user-agent : conda/4.7.5 requests/2.22.0 CPython/3.7.2 Linux/3.10.0-957.10.1.el7.ppc64le rhel/7.6 glibc/2.17
UID:GID : 1001:1001
netrc file : None
offline mode : False
```

L'issue non indica alcun file del repository, test o punto di ingresso della build. Inizia esaminando le istruzioni di configurazione e build del repository per VTK Python wheels, insieme alla toolchain disponibile per ppc64le e conda. Il lavoro sarebbe completato quando fosse disponibile un percorso documentato e riproducibile per compilare il Python-wrapped package sulla piattaforma indicata.

Scritto dal modello di indicizzazione a partire dal testo della issue.