[test] Fix -Wunused-parameter warnings
diff --git a/test/api/test-c.c b/test/api/test-c.c
index 4b43b83..78d6e97 100644
--- a/test/api/test-c.c
+++ b/test/api/test-c.c
@@ -58,7 +58,7 @@
 #endif
 
 int
-main (int argc, char **argv)
+main (void)
 {
   return !*hb_shape_list_shapers ();
 }