diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index 32652ded2d..344c2dfc3e 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -973,7 +973,7 @@ void xdl_free_script(xdchange_t *xscr) {
 	}
 }
 
-static int xdl_call_hunk_func(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+static int xdl_call_hunk_func(xdfenv_t *xe UNUSED, xdchange_t *xscr, xdemitcb_t *ecb,
 			      xdemitconf_t const *xecfg)
 {
 	xdchange_t *xch, *xche;