GHC doesn't doesn't clean up the way it should

Hi again,

Here's a mini-bug.

I'm playing around with adding preprocessors to GHC. I'm using the flags -F
and -pgmF for that. Since these are not terribly well documented I wanted to
run with -v to see what happens. This showed the following:

*** Haskell pre-processor
trharp TestHarp.hs TestHarp.hs
c:\DOCUME~1\JOSEFS~1\LOKALA~1\Temp\ghc2708.hspp
...
*** Deleting temp files
Deleting: c:/DOCUME~1/JOSEFS~1/LOKALA~1/Temp/ghc2708.hc
Warning: deleting non-existent c:/DOCUME~1/JOSEFS~1/LOKALA~1/Temp/ghc2708.hc


Seems like GHC didn't remember the suffix of the file to delete. 

This happens with 6.2.1.

I also would like some more documentation on -F. Why does it send the
program to be mangled twice to the pre-processor for instance?

Cheers,

        /Josef