[libre-riscv-dev] nMIgen now generates C++ models through yosysCXX!!!

[Yehowshua]

> 
> Yes quite odd... will just report this to whitequark on the nmigen
> github issue I created.

Sometimes - nMigen doesn’t always upgrade cleanly for me.
It also possible you have have installed two different versions of nMigen.
 Usually, `pip remove nmigen` and then `pip install git+https://github.com/nmigen/nmigen`
Fixes such things for me.

Yehowshua