On Friday, 19 June 2020 22:19:39 BST Hervé Guillemet wrote:
> Hello,
> 
> I need to distribute some linux binaries and the one built with my
> up-to-date gentoo sytem won't run on distributions using older glibc.
> 
> My idea is too maintain a gentoo chroot dedicated for compiling my
> binaries which would (package.)mask recent versions of glibc and gcc
> ebuilds.
> 
> What's the better way to go ? If I start with some of the stage3
> available for download, I won't be able to downgrade the glibc.
> 
> Or do you have any suggestion for alternatives to this gentoo chroot ?
> (I'd prefer avoid installing some CentOS or Ubuntu as virtual guests).

Once you chroot, you're in the chrooted env.  As long as you have a stage 3 
old enough to contain the requisite glibc, you should be good to go:

http://gentoo.osuosl.org/releases/amd64/