(c-macro-expansion): Use system-tmp-directory.

diff --git a/lisp/progmodes/cmacexp.el b/lisp/progmodes/cmacexp.el
index 7087f9e1cf08f2cd63d164397f56def5fae6182a..93ce065b6d59ccc5f3127ce5c099e7175019b098 100644 (file)
--- a/lisp/progmodes/cmacexp.el
+++ b/lisp/progmodes/cmacexp.el
@@ -265,10 +265,7 @@ Optional arg DISPLAY non-nil means show messages in the echo area."
        (startstat ())
        (startmarker "")
        (exit-status 0)
-       (tempname (make-temp-name (concat
-                                  (or (getenv "TMPDIR") (getenv "TEMP")
-                                      (getenv "TMP") "/tmp")
-                                  "/"))))
+       (tempname (make-temp-name (file-name-directory system-tmp-directory))))
     (unwind-protect
        (save-excursion
          (save-restriction