fix use of `eqv?` with `+inf.0`

The current Racket implementation preserves the `eq?`ness of `+inf.0`
enough to mostly hide this problem.

parser-tools-lib/parser-tools/private-lex/re.rkt

@@ -172,7 +172,7 @@
         ((and (= 0 low) (or (= 0 high) (eq? z r))) e)
         ((and (= 1 low) (= 1 high)) r)
         ((and (repeatR? r)
-              (eq? (repeatR-high r) +inf.0)
+              (eqv? (repeatR-high r) +inf.0)
               (or (= 0 (repeatR-low r))
                   (= 1 (repeatR-low r))))
          (build-repeat (* low (repeatR-low r))

parser-tools-lib/parser-tools/private-lex/stx.rkt

@@ -84,7 +84,7 @@
                                      stx
                                      (car arg-list)))
                (unless (or (and (number? high) (exact? high) (integer? high) (>= high 0))
-                           (eq? high +inf.0))
+                           (eqv? high +inf.0))
                  (raise-syntax-error #f
                                      "not a non-negative exact integer or +inf.0"
                                      stx