Tweak temporary-file-directory on darwin systems.

* lisp/files.el (temporary-file-directory): On darwin, also try
DARWIN_USER_TEMP_DIR (see discussion in bug#7135).

lisp/ChangeLog

+2010-10-01  Glenn Morris  <rgm@gnu.org>
+
+	* files.el (temporary-file-directory): On darwin, also try
+	DARWIN_USER_TEMP_DIR (see discussion in bug#7135).
+
 2010-10-01  Juanma Barranquero  <lekktu@gmail.com>
 	* server.el (server-start): Revert part of 2010-09-30T02:53:26Z!lekktu@gmail.com.

lisp/files.el

@@ -190,12 +190,27 @@ If the buffer is visiting a new file, the value is nil.")
 
 (defcustom temporary-file-directory
   (file-name-as-directory
+   ;; FIXME ? Should there be Ftemporary_file_directory to do the
+   ;; following more robustly (cf set_local_socket in emacsclient.c).
+   ;; It could be used elsewhere, eg Fcall_process_region, server-socket-dir.
+   ;; See bug#7135.
    (cond ((memq system-type '(ms-dos windows-nt))
 	  (or (getenv "TEMP") (getenv "TMPDIR") (getenv "TMP") "c:/temp"))
+	 ((eq system-type 'darwin)
+	  (or (getenv "TMPDIR") (getenv "TMP") (getenv "TEMP")
+	      (let ((tmp (ignore-errors (shell-command-to-string ; bug#7135
+					 "getconf DARWIN_USER_TEMP_DIR"))))
+		(and (stringp tmp)
+		     (setq tmp (replace-regexp-in-string "\n\\'" "" tmp))
+		     ;; This handles "getconf: Unrecognized variable..."
+		     (file-directory-p tmp)
+		     tmp))
+	      "/tmp"))
 	 (t
 	  (or (getenv "TMPDIR") (getenv "TMP") (getenv "TEMP") "/tmp"))))
   "The directory for writing temporary files."
   :group 'files
+  ;; Darwin section added 24.1, does not seem worth :version bump.
   :initialize 'custom-initialize-delay
   :type 'directory)