Okay, your readline capabilities are provided by libedit, not libreadline. That might be the difference. I'll compile python without readline tonight to see if I can reproduce.I fixed up and squashed the commits (you're still the author), but I want to make sure I take a look at and understand the bpo issue before letting this in.
By the way, are you using libedit or libreadline? You just need to provide the output of
```sh
python3 -c 'import readline; print(readline.__doc__)'
```In fact, the prompt message should be printed to stderr, so you want to use `printerr` instead. You can add an `end` kwarg to the current `printerr`.