Fix harmless unused parameter warnings in minimal build.

No real changes, just add some wxUnusedVar() to avoid warnings about
parameters unused in some non-default build configurations.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66090 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/evtloop.cpp

@@ -91,10 +91,12 @@ void wxGUIEventLoop::WakeUp()
 
 extern "C"
 {
-static gboolean wx_on_channel_event(GIOChannel * WXUNUSED_UNLESS_DEBUG(channel),
+static gboolean wx_on_channel_event(GIOChannel *channel,
                                     GIOCondition condition,
                                     gpointer data)
 {
+    wxUnusedVar(channel); // Unused if !wxUSE_LOG || !wxDEBUG_LEVEL
+
     wxLogTrace(wxTRACE_EVT_SOURCE,
                "wx_on_channel_event, fd=%d, condition=%08x",
                g_io_channel_unix_get_fd(channel), condition);