updated for version 7.4.684

Problem:    When starting several Vim instances in diff mode, the temp files
            used may not be unique. (Issue 353)
Solution:   Add an argument to vim_tempname() to keep the file.

src/os_unix.c

@@ -5838,7 +5838,7 @@ mch_expand_wildcards(num_pat, pat, num_file, file, flags)
     /*
      * get a name for the temp file
      */
-    if ((tempname = vim_tempname('o')) == NULL)
+    if ((tempname = vim_tempname('o', FALSE)) == NULL)
     {
 	EMSG(_(e_notmp));
 	return FAIL;