[xmonad] can't configure xmonad with the latest GHC

[Valery V. Vorotyntsev]

Houston, I've got a problem.

Having the latest GHC from darcs installed, I cannot configure xmonad
any more.

vvv at fun:~/src/xmonad$ runhaskell Setup.lhs clean
cleaning...

vvv at fun:~/src/xmonad$ runhaskell Setup.lhs configure --user --prefix=$HOME
Configuring xmonad-0.4...
Setup.lhs: At least the following dependencies are missing:
    base <3, unix -any

vvv at fun:~/src/xmonad$ runhaskell Setup.lhs configure --prefix=$HOME
Configuring xmonad-0.4...
Setup.lhs: At least the following dependencies are missing:
    X11 ==1.4.0, mtl -any

The dependencies are actually there, AFAIU:

vvv at fun:~/src/xmonad$ ghc-pkg list
/home/vvv/lib/ghc-6.9.20071125/package.conf:
    Cabal-1.3, array-0.1, base-3.0, bytestring-0.9, containers-0.1,
    directory-1.0, filepath-1.1, (ghc-6.9.20071125), haskell98-1.0.1,
    hpc-0.5, old-locale-1.0, old-time-1.0, packedstring-0.1,
    pretty-1.0, process-1.0, random-1.0, readline-1.0.1, rts-1.0,
    template-haskell-2.2, unix-2.2
/home/vvv/.ghc/i386-linux-6.9.20071125/package.conf:
    X11-1.4.0, mtl-1.1.0.0

A hint is highly welcome. ;)

--
vvv