[Jamin] Patch for session filename

[Emmanuel S. <esa...@fr...>]

Hi,

Here is a little patch to have a session filename management more
consistent IMHO.

This patch is needed for the second patch I will send (if this one is
accepted). My second patch will be intented to use gtk_file_chooser_*
instead of gtk_file_selection_* when GTK+ >= 2.4. But to do that we must
have a dynamically allocated global session filename (this current patch
make it possible):

* Renamed "filename" -> "session_filename".

* Renamed "s_*_filename()" -> "s_*_session_filename()".

* Added cleanup in "quit_clean()" for "session_filename".

* Always use "s_get/set_session_filename()" to manipulate
"session_filename" variable.

Tell me if it is ok for you. If so, I will send the second patch.

Thanks,

Bye