Checking PATH for python binaries

I noticed on the recent 1.95 release that Mac (and presumably Windows) binaries don’t show most input generators because the path to Python isn’t set.

(Well, it’s set to something like /usr/runner/bin/python3 based on paths on the GitHub build servers.)

I think there should be a fallback when python doesn’t exist at that path. The code should look through the user’s PATH environment variable for python3 or python.exe etc. and try the first one.

Not ideal, but it seems better than having most the Python scripts fail…

Thoughts? Ideas? Suggestions welcome…