https://bugs.gentoo.org/944264

--- a/src/config_utils.c
+++ b/src/config_utils.c
@@ -29,7 +29,7 @@
 #include "config_utils.h"
 
 static void
-usage ()
+usage (char* a)
 {
   g_printerr (_
   ("maitretarot [-h | -- help] [-v | --version] [-p port] [-c filename]\n"));