Comment by wizzwizz4

> Linux and OSX, for example, cannot run software compiled 20 years ago (I'd love to be proven wrong, but my experience hasn't been so great!).

Just get the copy of libc it was compiled for (and any other libraries), and add them to LD_LIBRARY_PATH before running the program. Linux's ABI is stable, so this should work fine. (It's always worked for me – though I haven't tried terribly much software, I'll admit.)

I don't know about macOS; iOS has compatibility problems, but Android basically doesn't.