updated for version 7.4.369
Problem: Using freed memory when exiting while compiled with EXITFREE.
Solution: Set curwin to NULL and check for that. (Dominique Pelle)
diff --git a/src/buffer.c b/src/buffer.c
index 7a6dbc5..5a9f8a7 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5702,8 +5702,8 @@
signlist_T *next;
/* When deleting the last sign need to redraw the windows to remove the
- * sign column. */
- if (buf->b_signlist != NULL)
+ * sign column. Not when curwin is NULL (this means we're exiting). */
+ if (buf->b_signlist != NULL && curwin != NULL)
{
redraw_buf_later(buf, NOT_VALID);
changed_cline_bef_curs();