patch 9.0.1336: functions without arguments are not always declared properly

Problem:    Functions without arguments are not always declared properly.
Solution:   Use "(void)" instead of "()". (Yegappan Lakshmanan, closes #12031)

src/if_lua.c

@@ -2736,7 +2736,7 @@ set_ref_in_lua(int copyID)
 }
 
     void
-update_package_paths_in_lua()
+update_package_paths_in_lua(void)
 {
     if (!lua_isopen())
 	return;