speaking of that, did you see whitequark's "superlnker" project ? (https://github.com/whitequark/superlinker)

it is a tool that can link a binary and all its dynamic dependencies together into one self-contained binary, even the dynamic linker itself (so the resulting binary can still use dlopen)

it would be risky to use it for production-level distributed software, but i imagine one could use it trivially on bitcoind to make a fully self-contained binary