vim-patch:8.0.0159

References #5406

Problem:    Using a NULL pointer when using feedkeys() to trigger drawing a
            tabline.
Solution:   Skip drawing a tabline if TabPageIdxs is NULL. (Dominique Pelle)
            Also fix recursing into getcmdline() from the cmd window.

c695cec469

src/nvim/screen.c

@@ -6884,7 +6884,10 @@ static void draw_tabline(void)
   int use_sep_chars = (t_colors < 8
                        );
 
-  redraw_tabline = FALSE;
+  if (ScreenLines == NULL) {
+    return;
+  }
+  redraw_tabline = false;
 
 
   if (tabline_height() < 1)