bug#68246: 30.0.50; Add non-TS mode as extra parent of TS modes

[Stefan Monnier]

>> In the longer term, there might be a fair bit of overlap, yes, tho it
>> all depends on how your proposal works out in the end.
>> My patch is a short term solution with no new API.
> Problem is, as you know, there's nothing more permanent than
> a short-term solution.

It's not meant to be temporary, tho, so it's not a problem.
We may need to undo it if it encounters problems, of course.


        Stefan