session management support

[Carsten Schaar <nhadcasc fs-maphy uni-hannover de>]

Moin moin,

after playing around with the gnome session management support in
libgnomeui, I started to add some things to the library.  This ended
in a complete rewrite of the gnome session management support, which
is (in my opinion) a little bit more gtk-ish than the now used
support, and has some additional features:

* Support for more than one session management client (This could be a
different aproach to the InitializationCommand problem.  It also
should 
be possible to rewrite a more tolerant 'smproxy' program with gnome
config file support)
* The properties, that are required by the XSMP protocol, are set
automatically, when creating a new gnome_client object.
* The session id is read automtically from the given command line
parameters, when creating a new gnome_client object.
* Invocation of callbacks in case of a session management message are
handled with gtk signals (except the INTERACT message).
* The program can receive a signal if the connection to the session
manager gets cut.

I wasn't able to get the latest gnome version yet, so I didn't made a
diff, but I put the code to the web.  The URL is:

http://www.fs-maphy.uni-hannover.de/~nhadcasc/download/gnome-client.tar.gz

The tar-file includes the two files 'gnome-client.h' and
'gnome-client.c' which are a replacement for 'gnome-session.*' and a
small example program 'ask.c'.  This example just asks you, whenever
you perform a shutdown, if you really want to shutdown (It's not very
usefull, but shows how to use gnome-client)

I would like this code to be understood as a proposal, and would
especially like Tom Tromey to have a look (and possibly a comment) on
this.

Ciao,
Carsten

-- 
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Carsten Schaar                         email: nhadcasc@fs-maphy.uni-hannover.de