patch 7.4.1611
Problem:    The versplit feature makes the code uneccessary complicated.
Solution:   Remove FEAT_VERTSPLIT, always support vertical splits when
            FEAT_WINDOWS is defined.
diff --git a/src/misc2.c b/src/misc2.c
index e247a92..ca340b7 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -169,7 +169,7 @@
 
 	if (finetune
 		&& curwin->w_p_wrap
-# ifdef FEAT_VERTSPLIT
+# ifdef FEAT_WINDOWS
 		&& curwin->w_width != 0
 # endif
 		&& wcol >= (colnr_T)width)
@@ -3633,7 +3633,7 @@
     }
     if (mouse && drag_status_line)
 	return SHAPE_IDX_SDRAG;
-# ifdef FEAT_VERTSPLIT
+# ifdef FEAT_WINDOWS
     if (mouse && drag_sep_line)
 	return SHAPE_IDX_VDRAG;
 # endif