diff --git a/src/drawline.c b/src/drawline.c
index 0d7c5b4..b58e837 100644
--- a/src/drawline.c
+++ b/src/drawline.c
@@ -369,7 +369,7 @@
  * Start a screen line at column zero.
  */
     static void
-win_line_start(win_T *wp, winlinevars_T *wlv)
+win_line_start(win_T *wp UNUSED, winlinevars_T *wlv)
 {
     wlv->col = 0;
     wlv->off = (unsigned)(current_ScreenLine - ScreenLines);