patch 8.0.1135: W_WINCOL() is always the same

Problem:    W_WINCOL() is always the same.
Solution:   Expand the macro.
diff --git a/src/ui.c b/src/ui.c
index c26cb37..64553b1 100644
--- a/src/ui.c
+++ b/src/ui.c
@@ -2845,7 +2845,7 @@
 #endif
 
 	row -= W_WINROW(curwin);
-	col -= W_WINCOL(curwin);
+	col -= curwin->w_wincol;
 
 	/*
 	 * When clicking beyond the end of the window, scroll the screen.