bpo-32101: Add PYTHONDEVMODE environment variable by vstinner · Pull Request #4624 · python/cpython

Ok, the patch now works properly, and the full Python test suite pass with PYTHONDEVMODE=1.

@ncoghlan, @pitrou: What do you think of adding sys.flags.dev_mode?

I chose to make sys.flags.dev_mode a boolean, whereas other flags are integer and have a Py_xxx variable in C.