bug#71796: [PATCH] Do not depend on tmpnam in posix.test.

`tmpnam' is a deprecated procedure that can be excluded during a
configure (`--disable-tmpnam').  There currently was a single test
relying on it, and therefore failing is such configuration.  This commit
switches to mkstemp instead.

* test-suite/tests/posix.test ("system*"): Use mkstemp instead of
tmpnam.
---
 test-suite/tests/posix.test | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/test-suite/tests/posix.test b/test-suite/tests/posix.test
index 18dad8902..0d75eb145 100644
--- a/test-suite/tests/posix.test
+++ b/test-suite/tests/posix.test
@@ -362,7 +362,8 @@
 
   (pass-if-equal "https://bugs.gnu.org/52835"
       "bong\n"
-    (let ((file (tmpnam)))
+    (let* ((port (mkstemp "T-XXXXXX"))
+           (file (port-filename port)))
       ;; Redirect stdout and stderr to FILE.
       (define status
         (call-with-output-file file
@@ -373,8 +374,9 @@
                   (lambda ()
                     (system* "sh" "-c" "echo bong >&2"))))))))
 
+      (delete-file file)
       (and (zero? (status:exit-val status))
-           (call-with-input-file file get-string-all))))
+           (get-string-all port))))
 
   (pass-if-equal "https://bugs.gnu.org/63024"
       0
-- 
2.45.1