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/memline.c b/src/memline.c
index d62697d..730496c 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -757,7 +757,7 @@
/* For a spell buffer use a temp file name. */
if (buf->b_spell)
{
- fname = vim_tempname('s');
+ fname = vim_tempname('s', FALSE);
if (fname != NULL)
(void)mf_open_file(mfp, fname); /* consumes fname! */
buf->b_may_swap = FALSE;