Ommitted parameter names is a C23 feature.

Index: benchmark.c
--- benchmark.c.orig
+++ benchmark.c
@@ -40,7 +40,7 @@ static volatile bool finished = false;
 
 /** interruptBench is used to stop the current benchmark */
 static void
-interruptBench(int) {
+interruptBench(int dummy) {
   finished = true;
 }
 
