Commits 205c59367c and
325e7e1824 introduced real glibc store paths from
current nixpkgs unstable into the source. Since nixpkgs `fetchFromGitea` (and
similar fixed-output derivations) depends on a C library, on x86_64-linux they
will fail with the forbidden reference error:
error: the fixed-output derivation '/nix/store/wnmnj3jzc82y89sfmyicr04kilg8zs2k-source.drv' must not reference store paths but 1 such references were found:
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66
Falsify the store path to prevent this failure.
Change-Id: I949033567bcad070f9a0a19cefdb33a79222e421