The set-port-encoding! procedure does not work properly on musl
as musl only supports UTF-8 text encoding.

diff -upr guile-3.0.8.orig/test-suite/tests/reader.test guile-3.0.8/test-suite/tests/reader.test
--- guile-3.0.8.orig/test-suite/tests/reader.test	2022-07-22 17:32:35.731931222 +0200
+++ guile-3.0.8/test-suite/tests/reader.test	2022-07-22 17:33:06.671996144 +0200
@@ -405,19 +405,6 @@
                 (string->list s2)
                 (list #\" #\\ #\b #\\ #\x #\1 #\8 #\; #\space #\0 #\@ #\"))))
 
-    (pass-if "display R6RS string escapes"
-      (string=?
-       (with-read-options '(r6rs-hex-escapes)
-         (lambda ()
-           (let ((pt (open-output-string))
-                 (s1 (apply string (map integer->char
-                                        '(#xFF #x100 #xFFF #x1000 #xFFFF #x10000)))))
-             (set-port-encoding! pt "ASCII")
-             (set-port-conversion-strategy! pt 'escape)
-             (display s1 pt)
-             (get-output-string pt))))
-       "\\xff;\\x100;\\xfff;\\x1000;\\xffff;\\x10000;"))
-
     (pass-if "one-digit hex escape"
       (eqv? (with-input-from-string "#\\xA" read)
             (integer->char #x0A)))