[gtkmm-documentation] Examples: Remove some uses of GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED

[Murray Cumming <murrayc src gnome org>]

commit 1e5e416218b238c83c48c65ff06de3730ca335da
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue May 12 08:48:58 2015 +0200

    Examples: Remove some uses of GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED
    
    Because we don't use that anymore and it makes the code less clear.

 examples/book/drawingarea/clock/clock.cc           |    5 -----
 examples/book/treeview/popup/treeview_withpopup.cc |    5 -----
 2 files changed, 0 insertions(+), 10 deletions(-)
---
diff --git a/examples/book/drawingarea/clock/clock.cc b/examples/book/drawingarea/clock/clock.cc
index 2cf8680..89c0c3d 100644
--- a/examples/book/drawingarea/clock/clock.cc
+++ b/examples/book/drawingarea/clock/clock.cc
@@ -26,11 +26,6 @@ Clock::Clock()
 : m_radius(0.42), m_line_width(0.05)
 {
   Glib::signal_timeout().connect( sigc::mem_fun(*this, &Clock::on_timeout), 1000 );
-
-  #ifndef GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED
-  //Connect the signal handler if it isn't already a virtual method override:
-  signal_draw().connect(sigc::mem_fun(*this, &Clock::on_draw), false);
-  #endif //GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED
 }
 
 Clock::~Clock()
diff --git a/examples/book/treeview/popup/treeview_withpopup.cc 
b/examples/book/treeview/popup/treeview_withpopup.cc
index f89c15d..b91ba14 100644
--- a/examples/book/treeview/popup/treeview_withpopup.cc
+++ b/examples/book/treeview/popup/treeview_withpopup.cc
@@ -60,11 +60,6 @@ TreeView_WithPopup::TreeView_WithPopup()
 
   m_Menu_Popup.accelerate(*this);
   m_Menu_Popup.show_all(); //Show all menu items when the menu pops up
-
-#ifndef GLIBMM_DEFAULT_SIGNAL_HANDLERS_ENABLED
-  signal_button_press_event()
-    .connect(sigc::mem_fun(*this, &TreeView_WithPopup::on_button_press_event), false);
-#endif
 }
 
 TreeView_WithPopup::~TreeView_WithPopup()