[guile-lib] PATCH: fix primes.scm

[Zack Weinberg]

primes.scm appears never to have been updated for the new bitvector API
(in Guile 3?), causing both build and test failures.

The appended patch (vs 0.2.8.1) fixes the failures I am seeing.
Assuming this is indeed an API change in Guile 3, I do not know what it
would take to make this code work with both, and I ask that you take it
from here.

zw

--- a/src/math/primes.scm       2024-05-23 19:26:16.757865343 -0400
+++ b/src/math/primes.scm       2024-05-23 19:28:20.797358650 -0400
@@ -114,7 +114,7 @@
                      (set! prime:prime-sqr (* nexp nexp))
                      (set! prime:sieve (make-bitvector nexp #f))
                      (for-each (lambda (prime)
-                                 (bitvector-set! prime:sieve prime #t))
+                                 (bitvector-set-bit! prime:sieve prime))
                                primes)
                      (set! prime:products (reverse (cons comp comps))))
                     (else
@@ -132,7 +132,7 @@
 There is a slight chance, @code{(expt 2 (- prime:trials))}, that a 
 composite will return @code{#t}."
   (set! n (abs n))
-  (cond ((< n (bitvector-length prime:sieve)) (bitvector-ref prime:sieve n))
+  (cond ((< n (bitvector-length prime:sieve)) (bitvector-bit-set? prime:sieve 
n))
        ((even? n) #f)
        ((primes-gcd? n prime:products) #f)
        ((< n prime:prime-sqr) #t)