filepath mangling under Windows?

[Malcolm Wallace]

With ghc-5.02.2 running from a Makefile in a cygwin shell under
Windows XP, the following behaviour occurs:

    ghc -package lang -package posix -c
        -o /d/haskell/hmake-3.00/targets/ix86-CYGWIN_NT-5.1/obj/hmake/QSort.o
        QSort.hs
    Assembler messages: FATAL: Can't create 
        \d\haskell\hmake-3.00\targets\ix86-CYGWIN_NT-5.1\obj\hmake\QSort.o:
        No such file or directory

It looks like ghc has reversed the slashes in the filepath given
to the -o option, and this is the reason the assembler fails.
The directory certainly exists, but we suspect cygwin only understands
the forward-slash form not the backward-slash form.

Is this a bug in ghc?  Or is there some option we can give to persuade
ghc not to reverse the slashes?

Regards,
    Malcolm