patch 8.1.2122: cannot build without terminal feature

Problem:    Cannot build without terminal feature.
Solution:   Add #ifdef.
diff --git a/src/window.c b/src/window.c
index 6174c02..0fda9f0 100644
--- a/src/window.c
+++ b/src/window.c
@@ -4654,9 +4654,11 @@
     maketitle();
 #endif
     curwin->w_redr_status = TRUE;
+#ifdef FEAT_TERMINAL
     if (bt_terminal(wp->w_buffer))
 	// terminal is likely in another mode
 	redraw_mode = TRUE;
+#endif
     redraw_tabline = TRUE;
     if (restart_edit)
 	redraw_later(VALID);	/* causes status line redraw */