Fix ./setup install comand (backport #10417)

[mergify]

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

Please read Github PR Conventions and then fill in one of these two templates.

---

Template Α: This PR modifies behaviour or interface

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.
• Manual QA notes have been included.
• Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)

---

Template B: This PR does not modify behaviour or interface

E.g. the PR only touches documentation or tests, does refactorings, etc.

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Is this a PR that fixes CI? If so, it will need to be backported to older cabal release branches (ask maintainers for directions).

---

This is an automatic backport of pull request #10417 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 2a178f2 has failed:

On branch mergify/bp/3.12/pr-10417
Your branch is up to date with 'origin/3.12'.

You are currently cherry-picking commit 2a178f243.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	new file:   cabal-testsuite/PackageTests/Install/DistPrefInstall/CHANGELOG.md
	new file:   cabal-testsuite/PackageTests/Install/DistPrefInstall/DistPrefInstall.cabal
	new file:   cabal-testsuite/PackageTests/Install/DistPrefInstall/Setup.hs
	new file:   cabal-testsuite/PackageTests/Install/DistPrefInstall/setup.test.hs
	new file:   cabal-testsuite/PackageTests/Install/DistPrefInstall/src/MyLib.hs
	new file:   changelog.d/t10416

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   Cabal/src/Distribution/Simple.hs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[geekosaur]

This can't be be backported to 3.12; it depends on SetupHooks which is 3.13+. Since it's a relatively small change that seems to be involved here, I'm poking at whether it can be rephrased not to require that, but I'm not hopeful.

[geekosaur]

Sadly, it's one line that's key to the whole thing and requires something not present in 3.12. CLosing.