[gtkmm] Tests: Fix a warning found by clang++.

[Murray Cumming <murrayc src gnome org>]

commit a9c34364b6d22020f118ff9470ccb1a7f0ba0093
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Mar 15 13:11:21 2012 +0100

    Tests: Fix a warning found by clang++.
    
    * tests/scrolledwindow/main.cc: Remove a macro check whose
    result is not used.

 ChangeLog                    |    7 +++++++
 tests/scrolledwindow/main.cc |    3 +--
 2 files changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 9da47e3..4f1f117 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2012-03-15  Murray Cumming  <murrayc murrayc com>
 
+	Tests: Fix a warning found by clang++.
+
+	* tests/scrolledwindow/main.cc: Remove a macro check whose
+	result is not used.
+
+2012-03-15  Murray Cumming  <murrayc murrayc com>
+
 	Main: Undeprecate init_gtkmm_internals().
 
 	* gtk/src/main.[hg|ccg]: This is used, for instance,
diff --git a/tests/scrolledwindow/main.cc b/tests/scrolledwindow/main.cc
index 2276493..16b0a35 100644
--- a/tests/scrolledwindow/main.cc
+++ b/tests/scrolledwindow/main.cc
@@ -2,9 +2,8 @@
 #include <gtk/gtk.h>
 #include <stdio.h>
 
-void on_viewport_destroyed(GtkWidget* widget, gpointer)
+void on_viewport_destroyed(GtkWidget*, gpointer)
 {
-  GTK_VIEWPORT(widget);
   g_warning("viewport destroyed");
 }