[racket] FFI require statement

Two days ago, Harry Spier wrote:
> The FFI require statement for the ImageMagick FFI is
> "(require mzlib/foreign) (unsafe!)"

Those examples are pretty old, and since then we switched away from
using the `unsafe!' declaration to a module with `unsafe' in its name.
I'll fix that -- but in the case of the magick interface a more
serious problem you have is that the library has (AFAICT) evolved
significantly since then.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!