proposal: add 'unsafeCoerce'

[Malcolm Wallace]

Currently, all implementations provide either the 'unsafeCoerce' or
'unsafeCoerce#' functions, but they live in implementation-specific
locations.  This proposal is to adopt the Haskell'98-compatible name
'unsafeCoerce', and to add it to the standard base library package.
Suggested location: Data.Function.Unsafe?

    http://hackage.haskell.org/trac/ghc/ticket/994

Regards,
    Malcolm