patch 8.1.1397: build fails in tiny version

Problem:    Build fails in tiny version.
Solution:   Always define hl_combine_attr().

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1397,
 /**/
     1396,
 /**/