In case anyone comes here with the same problem, the solution is:
attoparsec-aeson = haskellPackages.mkDerivation {
...
postUnpack = ''
mv source source-aeson
cp -rL source-aeson/attoparsec-aeson source
rm -fr source-aeson
'';
...
};
```*___*
It nails a different problem on the head.
You don’t have to convince the US government to allow you access to classified information, you just have to convince a lawyer that their (possibly non-US) client won’t be liable in case you are lying.