patch applied (ghc): Add a way to show what cleaning would be done, without actually doing it

[Ian Lynagh]

Sat May  8 05:24:38 PDT 2010  Ian Lynagh <igloo at earth.li>
  * Add a way to show what cleaning would be done, without actually doing it

    M ./mk/tree.mk +6

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20100508122438-3fd76-56b583f4c4146bf462f3649060f19e7e2d8196fe.gz