Fix stdstream initialization

Extract the keyword from the DEFAULT-EXTERNAL-FORMAT specification,
in case users have specified options in *DEFAULT-EXTERNAL-FORMAT*.

src/code/stream.lisp

@@ -2678,7 +2678,7 @@ benefit of the function GET-OUTPUT-STREAM-STRING."
                         ((sb-win32::console-handle-p fd)
                          :ucs-2)
                         (t
-                         (default-external-format))))
+                         (external-format-keyword (default-external-format)))))
          (ef (get-external-format keyword))
          (replacement (ef-default-replacement-character ef)))
     `(,keyword :replacement ,replacement)))

tests/stream.test.sh

@@ -16,6 +16,7 @@
 use_test_subdirectory
 
 tmpfilename="$TEST_FILESTEM.lisp"
+tmpcore="stream-test.core"
 
 cat > $tmpfilename <<EOF
     (in-package :cl-user)
@@ -63,5 +64,18 @@ if [ 'Bivalent *ERROR-OUTPUT*' != "$test_output" ]; then
     exit $EXIT_LOSE
 fi
 
+run_sbcl <<EOF
+  (setf sb-ext:*default-external-format* '(:utf-8 :newline :crlf))
+  (sb-ext:save-lisp-and-die "$tmpcore")
+EOF
+if [ $? -ne 0 ]; then
+    echo "failure saving core"
+    exit 1
+fi
+
+run_sbcl_with_core "$tmpcore" --disable-ldb  --noinform --no-sysinit --no-userinit --disable-debugger \
+                   --eval '(sb-ext:quit :unix-status 52)'
+check_status_maybe_lose "stdstream external format setting" $? 52 "(loading worked)"
+
 # success
 exit $EXIT_TEST_WIN