fix(Cabal): Fix install-includes with a local (relative) path

[zlonast]

fix: #11186

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[zlonast]

@sheaf Hi, can you point me in the right direction to solve this problem?

[sheaf]

I think packageRoot is terrible and I should have removed it in my working directory patch. I'm working on a patch which I'll put up soon.

[sheaf]

Here's a small patch that removes packageRoot entirely, which was the root cause of the bugs here: sheaf@673e020

On top of that patch, the fix here should be to remove the buildPref argument to installIncludeFiles entirely, changing findInc to have a type signature like findInc :: [SymbolicPath Pkg (Dir Include)] -> RelativePath Include File -> IO (RelativePath Include File, SymbolicPath Pkg File) instead of findInc :: [FilePath] -> FilePath -> IO (FilePath, FilePath). Everything else should be driven by the types and by using i = interpretSymbolicPathLBI lbi like elsewhere.

[zlonast]

@sheaf In that case, I think I'll close my PR in favor of your patch. Please cherry-pick my test into your branch.

[sheaf]

@sheaf In that case, I think I'll close my PR in favor of your patch. Please cherry-pick my test into your branch.

Understood, thanks for your work. I have put up #12310.