patch 8.2.3998: asan error for adding zero to NULL

Problem:    Asan error for adding zero to NULL.
Solution:   Do not compute pointer if there are no entries.
diff --git a/src/version.c b/src/version.c
index 170c0c2..4f40aab 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3998,
+/**/
     3997,
 /**/
     3996,