I've got this common error :
arch: posix_spawnp: /opt/local/bin/pythonw2.7: Bad CPU type in executable
With my favourite search engine, I explore the web and found some things like in the official documentation ( https://grasswiki.osgeo.org/wiki/MacOSX_GRASS_errors ) settings new python's environments variables. By the way, I put this in my ~/.bash_profile :
It's different to the official common MacOsX GRASS GIS errors but GRASS 7 require python2.7.
This procedure didn't work.
In the description of the bug, there is a problem between a wrong architecture : 32 vs 64 bits. I decided to download the latest revision of python 2.7 here : https://www.python.org/downloads/
And all I want to say is "It Works !"
Note : if you want to install BlenderGIS on your Mac, you can follow the procedure here : https://github.com/domlysz/BlenderGIS/issues/5
BlenderGIS require Gdal python bindings but with python 3.x, that's why I have a trouble with software requirements