Fix compiler warnings and enable -Wall -Werror

Change-Id: I24847fa35644d92bff0fe31ccfc5c4b3e8705779
diff --git a/clatd.c b/clatd.c
index 8199b7b..b305ef3 100644
--- a/clatd.c
+++ b/clatd.c
@@ -82,7 +82,7 @@
 /* function: stop_loop
  * signal handler: stop the event loop
  */
-void stop_loop(int signal) {
+void stop_loop() {
   running = 0;
 }