patch 8.0.0073
Problem:    More comparisons between firstwin and lastwin.
Solution:   Use ONE_WINDOW for consistency. (Hirohito Higashi)
diff --git a/src/option.c b/src/option.c
index c32a2a4..ecfdc40 100644
--- a/src/option.c
+++ b/src/option.c
@@ -8551,7 +8551,7 @@
 	}
 
 	/* Change window height NOW */
-	if (lastwin != firstwin)
+	if (!ONE_WINDOW)
 	{
 	    if (pp == &p_wh && curwin->w_height < p_wh)
 		win_setheight((int)p_wh);
@@ -8591,7 +8591,7 @@
 	}
 
 	/* Change window width NOW */
-	if (lastwin != firstwin && curwin->w_width < p_wiw)
+	if (!ONE_WINDOW && curwin->w_width < p_wiw)
 	    win_setwidth((int)p_wiw);
     }
 
@@ -10075,7 +10075,7 @@
 comp_col(void)
 {
 #if defined(FEAT_CMDL_INFO) && defined(FEAT_WINDOWS)
-    int last_has_status = (p_ls == 2 || (p_ls == 1 && firstwin != lastwin));
+    int last_has_status = (p_ls == 2 || (p_ls == 1 && !ONE_WINDOW));
 
     sc_col = 0;
     ru_col = 0;