Fix build issues with unused parameters

Change-Id: Iac7865506e72318a8d2b7b7128a328db75b36cbe
diff --git a/tests/ping_responder/helloc.cpp b/tests/ping_responder/helloc.cpp
index 8caa56f..5ed4568 100644
--- a/tests/ping_responder/helloc.cpp
+++ b/tests/ping_responder/helloc.cpp
@@ -44,7 +44,7 @@
 
 }  // namespace
 
-int main(int argc, char *argv[]) {
+int main(int /* argc */, char * /* argv */ []) {
   sp<IPingResponder> service;
   cout << "helloc: Retrieving ping service binder" << endl;
   status_t status = getService(String16(kServiceName), &service);