First attempt at native build for Apple M1 machines

Alpha Release for Apple M1

We’ve made an Alpha release of VisIt version 3.3.1 for native Apple M1 machines. This release does not yet support parallel or all database plugins. Features that were disabled, primarly to get to a point of early testing include Ospray, Adios2, Advio, Boxlib, GDAL, Icet, netCDF, PIDX, PySide, Xdmf, TBB, Embree. These will be included in a future M1 native release. We also did not package this release as a .dmg file or sign the release. That said, those who wish to give it a try should be able to download the release, untar it and follow the Linux install instructions.

We would appreciate any feedback at our GitHub discussions.