avoid invalid filepaths on Windows

[geekosaur]

Template Β: This PR does not modify cabal behaviour (documentation, tests, refactoring, etc.)

Include the following checklist in your PR:

• Patches conform to the coding conventions.

[ulysses4ever]

Thanks!

[Mikolaj]

Would you mind providing a link that, more or less, captures the rules you are using? Preferably with a version number or date of retrieval.

I've found something related:

Cabal-tests/tests/ParserTests/regressions/denormalised-paths.check:The paths 'files/<>/.txt', 'c/**/.c', 'C:foo/bar', '||s' are invalid on Windows, which would cause portability problems for this package. Windows file names cannot contain any of the characters ":*?<>|" and there a few reserved names including "aux", "nul", "con", "prn", "com1-9", "lpt1-9" and "clock$".

and

Cabal/ChangeLog.md- * With build-type: configure, avoid using backslashes to delimit
Cabal/ChangeLog.md: path components on Windows and warn about other unsafe characters
Cabal/ChangeLog.md- in the path to the source directory on all platforms
Cabal/ChangeLog.md- (#5386).

and

Cabal/src/Distribution/PackageDescription/Check.hs: [ check (not . FilePath.Windows.isValid . prettyShow . packageName $ pkg)

[geekosaur]

https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file is where I got the list I mentioned here.

[andreasabel]

Likely sound (excluding bad names), certainly not complete (excluding only bad names).
Maybe ok, since there are enough good names it let's through. ;-)

[andreasabel]

Thanks!