https://bugs.gentoo.org/944250

--- a/src/main.c
+++ b/src/main.c
@@ -244,7 +244,7 @@ void GameTimer(int v)
 }
 
 #ifdef CFG_GTK
-static gboolean DisplayDialog()
+static gboolean DisplayDialog(void* a)
 {
    GtkWidget * dialog = gtk_message_dialog_new(NULL,
       GTK_DIALOG_MODAL, GTK_MESSAGE_INFO, GTK_BUTTONS_OK, ASTEROIDS_ABOUT);