* etc/NEWS: Add entries for saving and restoring GDB window configurations. * doc/emacs/building.texi (GDB User Interface Layout): Add documentation for 'gdb-save-window-configuration', 'gdb-load-window-configuration', 'gdb-default-window-configuration-file', 'gdb-window-configuration-directory', 'gdb-restore-window-configuration-after-quit'. Change 'many-windows layout' to 'default layout'.