[WIP] Automated 3.9 update

[ethanhs]

So I automated everything. You can now run ./tools/scripts to run all of the scripts and commands to do everything step by step. (Well, enough to build anyway, it still has the issues from before).

(Responding to some of your messages from #137)

It seems ast.Ellipsis was deprecated and somehow didn't make it into your port? But mypy expects it.

Yeah I noticed that too. It's odd because the ASDL doesn't have the old nodes, but I couldn't figure out how CPython adds it back...

All that points to deeper problems. Probably it's easier for you.

Hmm, I really have no idea why that would happen. I probably should look more closely at typed_ast.c, I am not sure that things get initialized correctly... (I'll look into this tomorrow)

[gvanrossum]

It's odd because the ASDL doesn't have the old nodes, but I couldn't figure out how CPython adds it back...

CPython has an ast.py in the stdlib (Lib/ast.py) that starts with from * import _ast (which imports all the stuff defined in C code), but then adds various compatibility classes like Ellipsis and Bytes as pure Python classes.

[ethanhs]

Ah thanks! somehow I missed that. I'll include that in the files copied.

[gvanrossum]

@ethanhs Is this still valuable to you?

[ethanhs]

Unfortunately I don't think I will have time to get this to work :/

Maybe I'll pick it up again another time.