From looking at https://hydra.nixos.org/build/242634472 and https://hydra.nixos.org/build/242634509 it appears that the problem is the http-parser package, used by libgit2, is always trying to make an .so.

I have done the Nixpkgs fix backport ready and soon to be merged: NixOS/nixpkgs#271202 Hopefully that fixes it.