diff --git a/tests/gpgscm/ffi.c b/tests/gpgscm/ffi.c
index c37bf1daa..57de28614 100644
--- a/tests/gpgscm/ffi.c
+++ b/tests/gpgscm/ffi.c
@@ -1248,7 +1248,7 @@ ffi_init (scheme *sc, const char *argv0, int argc, const char **argv)
   ffi_define_function (sc, open);
   ffi_define_function (sc, fdopen);
   ffi_define_function (sc, close);
-  ffi_define_function (sc, mkdtemp);
+  ffi_define_function_name (sc, "_mkdtemp", mkdtemp);
   ffi_define_function (sc, unlink);
   ffi_define_function (sc, unlink_recursively);
   ffi_define_function (sc, rename);
diff --git a/tests/gpgscm/tests.scm b/tests/gpgscm/tests.scm
index f97b22e66..8283ebad9 100644
--- a/tests/gpgscm/tests.scm
+++ b/tests/gpgscm/tests.scm
@@ -247,10 +247,19 @@
        (chdir ,cwd-sym)
        ,result-sym)))
 
+;; Make a temporary directory.  If arguments are given, they are
+;; joined using path-join, and must end in a component ending in
+;; "XXXXXX".  If no arguments are given, a suitable location and
+;; generic name is used.
+(define (mkdtemp . components)
+  (_mkdtemp (if (null? components)
+		(path-join (getenv "TMP") "gpgscm-XXXXXX")
+		(apply path-join components))))
+
 (macro (with-temporary-working-directory form)
   (let ((result-sym (gensym)) (cwd-sym (gensym)) (tmp-sym (gensym)))
     `(let* ((,cwd-sym (getcwd))
-	    (,tmp-sym (mkdtemp (path-join (getenv "TMP") "gpgscm-XXXXXX")))
+	    (,tmp-sym (mkdtemp))
 	    (_ (chdir ,tmp-sym))
 	    (,result-sym (begin ,@(cdr form))))
        (chdir ,cwd-sym)
@@ -259,7 +268,7 @@
 
 (define (make-temporary-file . args)
   (canonical-path (path-join
-		   (mkdtemp (path-join (getenv "TMP") "gpgscm-XXXXXX"))
+		   (mkdtemp)
 		   (if (null? args) "a" (car args)))))
 
 (define (remove-temporary-file filename)
diff --git a/tests/openpgp/run-tests.scm b/tests/openpgp/run-tests.scm
index 367c64116..e3b6b6a47 100644
--- a/tests/openpgp/run-tests.scm
+++ b/tests/openpgp/run-tests.scm
@@ -128,7 +128,7 @@
 		      (unlink-recursively t::directory)
 		      (t::report)) results::procs)
 	  (exit (results::report)))
-	(let* ((wd (mkdtemp "gpgscm-XXXXXX"))
+	(let* ((wd (mkdtemp))
 	       (test (car tests'))
 	       (test' (test::set-directory wd))
 	       (setup' (setup::set-directory wd)))
@@ -154,7 +154,7 @@
 		      (unlink-recursively t::directory))
 		    results::procs)
 	  (exit (results::report)))
-	(let* ((wd (mkdtemp "gpgscm-XXXXXX"))
+	(let* ((wd (mkdtemp))
 	       (test (car tests'))
 	       (test' (test::set-directory wd))
 	       (setup' (setup::set-directory wd)))