When viewing ./configure's output in Emacs' compilation mode, "yes"
and "no" are coloured green and red respectively.  This makes it easy
to spot "offending" lines.  For other configure results, the result is
coloured blue... which is classed as a "warning".

Unfortunately a few lines are blue when they could/should be green or
red.  In particular, these are probably easy to fix:

     37:checking GHC.Handle.openFd... NOT old API
     38:checking GHC.Handle.openFd new API... NOT 'new' API
     39:checking GHC.Handle.fdToHandle' API... okay
     65:checking renameFile... okay

Similarly lines like this are always blue because they have stuff after "no/yes":

    checking for module Text.Regex( mkRegex, matchRegex, Regex )... no; and neither in package text

"Fixing" them by removing the information is a more controversial
move, and I'm not sure I agree with it.

I can no longer reproduce the "easy" examples, and the hard ones probably require
patching files from the GHC distribution, which makes the return on investment of
working on this not worth it.