[cvs-nhc98] patch applied (hat): Fix long-standing bug in @-patterns.

[Malcolm Wallace]

Mon Feb  5 10:35:26 PST 2001  malcolm
  * Fix long-standing bug in @-patterns.
    An @-pattern in a CAF (i.e. not in an argument position or lambda)
    generated incorrect code.  Example:
        main = let s at _ = "hello" in print s
    expected result "hello", actually gave "".

    M ./src/compiler98/Case.hs -10 +18