I find it's best to treat this as a case of "cross-compilation to old glibc version". That is, you don't want to just link against an old glibc version, you wan

I find it's best to treat this as a case of "cross-compilation to old glibc version". That is, you don't want to just link against an old glibc version, you want a full cross-compilation toolchain where the compiler does not pick up headers from `/usr/include` by default (but instead has its own copy of the system headers), and where libstdc++ is also linked against that old glibc version. We used https://crosstool-ng.github.io/ https://crosstool-ng.github.io/ to create such a "cross-compiler". Now it doesn't matter which distribution our developers use, the same source code will always turn into the same binary (reproducible builds, yay!) and those binaries will work on older distributions than the developers are using. This allows us to ship dynamically linked linux executables; our linux customers can just unzip + run, same as our windows customers, no need to mess with docker containers. The downside is that we can't just use a library by `apt install`ing it, everything needs to be built with the cross compilation toolchain.