patch applied (ghc): Check files are really created in libffi

[Ian Lynagh]

Sun Jun 20 09:37:24 PDT 2010  Ian Lynagh <igloo at earth.li>
  * Check files are really created in libffi
  when we think that the libffi build creates them, so they just depend
  on the libffi build stamp.

    M ./libffi/ghc.mk +6

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20100620163724-3fd76-e4d1efaecc98e42c2b99e125197a22a3b61f2485.gz