alt Hacker NewsAFAIK glibc is backwards compatible as long as a) your program is running on a newer version (i.e. you're not trying to dynamically link against an older version) and b) you're not using hidden/undocumented symbols.
In which case as long as you're using the documented public API and compile your program with the oldest version of glibc you want to support (some Ubuntu from 4-5 years ago should cover pretty much every current desktop) you should be fine. And with something like Docker this is trivial to do.
Sure it is annoying that you cannot use your current distro (especially if you use some rolling distro) to make binaries for everyone, but it takes very little effort to work around that. The only issue i can think of is if you absolutely want to compile using the latest version of your compiler and you cannot build the compiler from source to work in the Docker (or whatever) contain to work against the older glibc.
This approach only works for very simple cases.
In complex cases, it turns out that the old version of glibc also pulls in other libraries and the compiler, and you're stuck with a very ancient sysroot. You may often find that you can't compile new library versions in such a sysroot and link them statically.
So, it looks good on paper, but forget about the ravines.