Apply Bash 4.4.20 to fix cpu spinning on built-in wait

[Wiebe Cazemier]

Hi list,

Sometime ago, I made:

https://bugs.launchpad.net/ubuntu/+source/bash/+bug/1822776

Which is a about applying the Bash 4.4.20 patch to fix CPU spinning on a 'wait' command. It occurs on systems with high PID cycling, for instance when bash loops are used to repeatedly run commands.

Because Ubuntu 18.04 is only one patch level behind this, and because of the very nasty situations that can occur (and did, for me), I was hoping this patch would be included.

There don't seem to be any downsides?

Regards,

Wiebe