Linking to the rust library in racket.

blur-linkage.rkt

;; link to the rust library:
(define rust-lib (ffi-lib (build-path here "libblur-68a2c114141ca-0.0")))
(define rust-blur-fun (get-ffi-obj "blur" rust-lib (_fun _uint _uint _cvector -> _void)))

(define (rust-blur width height data)
  (define cvec (list->cvector data _byte))
  (rust-blur-fun width height cvec)
  (cvector->list cvec))