std.posix: handle INVAL in openZ and openatZ

Contributes to #15607

Although the case is not handled in `openatWasi` (as I could not get a
working wasi environment to test the change) I have added a FIXME
addressing it and linking to the issue.
b4e7b6fdbaKetan Reynolds committed on 7/29/2024, 2:01:55 AM· committed by Ryan Liptakparentc157550
1 file changedLine totals unavailable