patch applied (cabal-branches/cabal-1.2): Add an interfacedir configure flag, for where to put haddock insterface files

[Ian Lynagh]

Mon Oct 29 10:49:08 PDT 2007  Ian Lynagh <igloo at earth.li>
  * Add an interfacedir configure flag, for where to put haddock insterface files

    M ./Distribution/Simple/InstallDirs.hs -53 +65
    M ./Distribution/Simple/Register.hs -9 +15
    M ./Distribution/Simple/Setup.hs +7