mupdf: fix patch hash by fetchpatch

Thanks to @kirelagin for reporting on IRC.
cabal-install: use native Cabal version when compiling with GHC 7.9.x
haskell-platform-2012.4.0.0: fix incorrect version of 'network'
binary: fix build with ghc 6.10.4
haskell-DrIFT: add version 2.4.2
leksah: remove broken package
DrIFT: don't make this tool available with ghc <= 7.2.2

The build won't succeed.