patch 9.0.1859: heap-use-after-free in bt_normal()

Problem:  heap-use-after-free in bt_normal()
Solution: check that buffer is still valid

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index b604b57..f2ff8d6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1859,
+/**/
     1858,
 /**/
     1857,