csc -O5 -strict-types -fixnum-arithmetic: 7.964s
csc -O5 -strict-types:                    8.105s
csc -O5 -strict-types (and fx functions): 0.246s
c/nim -O3 baseline:                       0.211s

---

(define (fib n)
  (if (or (= n 0) (= n 1))
      n
      (+ (fib (- n 1)) (fib (- n 2)))))

(let loop ((n 0))
  (when (< n 35)
    (print "n=" n " => " (fib n))
    (loop (+ n 1))))