Building GHC

When I look at the instructions http://hackage.haskell.org/trac/ghc/wiki/Building/GettingTheSources they say the distribution is split in two but when I look at http://darcs.haskell.org/ it seems to be split in three ghc-HEAD-2007-12-16-..> 16-Dec-2007 14:25 102M ghc-HEAD-2007-12-16-..> 16-Dec-2007 14:20 92M ghc-HEAD-2007-12-16-..> 16-Dec-2007 14:12 57M I'm assuming I unpack these on top of each other but I'd be grateful if someone could confirm this. Thanks, Dominic.