patch applied (cabal): setup makefile: use -p option to mkdir when making object directories

[Simon Marlow]

Mon Apr 16 06:47:20 PDT 2007  Simon Marlow <simonmar at microsoft.com>
  * setup makefile: use -p option to mkdir when making object directories
  I had a feeble attempt to avoid needing this originally, using $(sort ...)
  to create parents before children, but sometimes the parents aren't in
  the list, so it doesn't work.  mkdir's -p option is POSIX, and I found
  it on all the platforms I checked (Linux, Solaris, Darwin, FreeBSD).

    M ./Distribution/Simple/GHC.hs -1 +1