Now try building a "portable" binary that runs on a version of Linux older than yours.

Isn't that simply a matter of targeting an older glibc? I am probably missing something though.

Yes, "simply". It's a very fun process. Around 100 times more fun than the onerous

  git config --global core.symlinks true

andrewmcwatters

Anyone who talks nonchalantly about glibc hasn't had their time eaten up by glibc.

Spivak

Like it’s absolutely a nightmare but you can eliminate a lot of problems by building on an ancient version of RHEL.

jeroenhd

It says a lot about Linux development that for cases like these "just install the Linux equivalent of Windows XP in a container and run the tools inside that" is an accepted solution.

It's a solution that works well and is used by loads of developers, but it's still comically silly.

account42

There are other approaches like https://github.com/wheybags/glibc_version_header or sysroots with older glibc, e.g. https://wiki.gentoo.org/wiki/Crossdev - you don't need your whole XP, just the the system libs to link against.

Sure, having a nice SDK where you can just specify the minimum vesion you want to support would be nice but who do you expect to develop such an SDK? GNU/glibc maintainers? They would rather you ship as source. Red Hat / SUSE / Canonical? They want you to target only their distro. Valve? They decided its easier to just provide an unchaning set of libraries since they need to support existing games that got things wrong anyway and already have a distribution platform to distribute such a base system along with the games without bundling it into every single one.