Replace deprecated g_binding_get_target, and increase glib version to 2.68

- debian stable (trixie) has 2.84.4
- oldstable (bookworm) has 2.74.6

Author: richardcohen

CMakeLists.txt

@@ -231,7 +231,7 @@ if (NOT PKG_CONFIG_FOUND)
  endif()
 
 # glib et al.
-set(GLIB_MIN_VERSION 2.56.1)
+set(GLIB_MIN_VERSION 2.68.1)
 set(GTK_MIN_VERSION 3.22.30)
 
 pkg_check_modules (GLIB2 REQUIRED IMPORTED_TARGET glib-2.0>=${GLIB_MIN_VERSION})

README.dependencies

@@ -55,7 +55,7 @@ Libraries/Deps
   --------              _______
   gcc or clang          8.0 (gcc)/6.0(clang)    C++17 C/C++ compiler
   cmake                 3.14.5                  Build system manager
-  glib2                 2.56.1
+  glib2                 2.68.1
   gtk+3                 3.22.30
   guile                 3.0, 2.2 or 2.0.9       Must be built with regex
                                                 support enabled

gnucash/gnome-utils/gnc-tree-view.c

@@ -1381,9 +1381,10 @@ gnc_tree_view_update_column_menu_item (GtkCheckMenuItem *checkmenuitem,
     else
     {
         GBinding *binding = g_object_get_data (G_OBJECT(checkmenuitem), "column-binding");
-        GtkTreeViewColumn *column = GTK_TREE_VIEW_COLUMN(g_binding_get_target (binding));
+        GtkTreeViewColumn *column = GTK_TREE_VIEW_COLUMN(g_binding_dup_target (binding));
 
         visible = gtk_tree_view_column_get_visible (column);
+        g_object_unref(column);
     }
     gtk_check_menu_item_set_active (checkmenuitem, visible);
 }