???

Okay what is it

`stack path --fast ...` says "Invalid option `--fast'"

From #haskell:

> that might change optimization and thereby the abi since cross-module
> inlining information will be absent with -O0 / no -O

privacypass Nix packaging is sensitive to the version and the one previously
selected is now too old

try to get around the timeout problem on slow CircleCI builders

it uses bash, at least.

```
--  While building package Cabal-2.4.1.0 using:
      /root/.stack/setup-exe-cache/x86_64-linux-nix/Cabal-simple_mPHDZzAJ_2.4.0.1_ghc-8.6.5 --builddir=.stack-work/dist/x86_64-linux-nix/Cabal-2.4.0.1 build --ghc-options "-hpcdir .stack-work/dist/x86_64-linux-nix/Cabal-2.4.0.1/hpc -ddump-hi -ddump-to-file -fdiagnostics-color=always"
    Process exited with code: ExitFailure (-9) (THIS MAY INDICATE OUT OF MEMORY)
    Logs have been written to: /root/project/.stack-work/logs/Cabal-2.4.1.0.log
```