patch applied (ghc): Change standalone deriving syntax and semantics; fixes trac #1481

[Ian Lynagh]

Fri Aug 10 15:37:28 PDT 2007  Ian Lynagh <igloo at earth.li>
  * Change standalone deriving syntax and semantics; fixes trac #1481
  You now say
      deriving instance Cxt => Head

    M ./compiler/parser/Lexer.x -3
    M ./compiler/parser/Parser.y.pp -3 +1
    M ./compiler/typecheck/TcDeriv.lhs -20 +42