Ticket #7448 (closed bug: wontfix)
Attached Python script detabs GHC source and removes the text "The above warning supression flag is a temporary kludge.". Detabbed version passed "sh validate" on my machine. Just like GHC, it uses tabstop 8, so it does not change semantics of the code.
To use, run "python detab.py" in the main source tree. It will overwrite tabs in all subdirectories; for a sample, it can be run in a subdirectory.
It leaves three files (TcSMonad.lhs, LibFFI.hs, LibFFI.hsc) unchanged because the warning there is not exactly the same, but this is a minor issue.