* src/Makefile.am (global_defines): Add -DGTKMM_DISABLE_DEPRECATED.

* src/filetree.cc (FileTree::FileTree): Replace the deprecated
set_sort_column_id() by set_sort_column().
* src/filetreeprivate.cc
(FileTree::ScopedBlockSorting::ScopedBlockSorting): ditto
(FileTree::ScopedBlockSorting::~ScopedBlockSorting): ditto.

* src/mainwindow.cc (MainWindow::on_go_next): Use scroll_to()
in place of the deprecated scroll_to_mark().