Add [[maybe_unused]] to silence unhelpful warnings

qswiki.cpp

@@ -43,7 +43,7 @@ SOFTWARE.
 #include "cliserver.h"
 #include "version.h"
 
-void sigterm_handler(int arg)
+void sigterm_handler([[maybe_unused]] int arg)
 {
 	// TODO: proper shutdown.
 	exit(EXIT_SUCCESS);