Message 132000 - Python tracker

> Antoine Pitrou wrote:
> > It would be nice if it were enabled by default for fatal errors (and asserts perhaps?).
> 
> I feel like a broken record. This code hardcodes fd=2 as a write target on crash,

For fatal errors, you needn't be async-safe, so the fatal error code
could read fileno(stderr) and give it to the traceback printing code.
What do you think, Victor?