Running ./setup install will give you an error:

```
fromFlag NoFlag. Use fromFlagOrDefault
CallStack (from HasCallStack):
  error, called at src/Distribution/Simple/Flag.hs:110:19 in Cabal-3.15.0.0-inplace:Distribution.Simple.Flag
  fromFlag, called at src/Distribution/Simple/Register.hs:161:16 in Cabal-3.15.0.0-inplace:Distribution.Simple.Register
```

This seems to not be tested anywhere and most people will use ./setup
register in any case, but we should fix this for the next point release
in 3.14 series. # Please enter the commit message for your changes.
Lines starting

Fixes #10416

(cherry picked from commit 2a178f24)