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.
diff --git a/src/if_cscope.c b/src/if_cscope.c
index f72a96b..2b4ba08 100644
--- a/src/if_cscope.c
+++ b/src/if_cscope.c
@@ -1269,7 +1269,7 @@
     {
 	/* fill error list */
 	FILE	    *f;
-	char_u	    *tmp = vim_tempname('c');
+	char_u	    *tmp = vim_tempname('c', TRUE);
 	qf_info_T   *qi = NULL;
 	win_T	    *wp = NULL;