patch 8.1.1397: build fails in tiny version

Problem:    Build fails in tiny version.
Solution:   Always define hl_combine_attr().
diff --git a/src/version.c b/src/version.c
index 65a7b96..0e7f14d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1397,
+/**/
     1396,
 /**/
     1395,