bug#48117: 28.0.50; Update of loaddefs.el during normal build is unreliable

[Eli Zaretskii]

> Date: Fri, 30 Apr 2021 17:32:13 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: 48117@debbugs.gnu.org
> 
> Can ldefs-boot.el not be used to detect whether loaddefs.el needs to be 
> regenerated?

I believe that's what Glenn suggested a few minutes ago.