print a warning when starting Gtk+ emacs in daemon mode

[Dan Nicolaescu]

We get many duplicate bug reports of Gtk+ emacs crashing when run in
daemon mode and the X11 connection dies.

How about printing a warning when starting Gtk+ emacs in daemon mode so
that the users are aware of the potential risks (and blame Gtk+ not
emacs ...)

OK?

=== modified file 'src/emacs.c'
--- src/emacs.c   2011-05-31 05:12:19 +0000
+++ src/emacs.c   2011-05-31 06:42:45 +0000
@@ -1002,6 +1002,11 @@ main (int argc, char **argv)
   }
 
 #ifndef NS_IMPL_COCOA
+#ifdef USE_GTK
+      fprintf (stderr, "Warning: due a long standing Gtk+ 
bug\nhttp://bugzilla.gnome.org/show_bug.cgi?id=85715\n\
+Emacs might crash when run in deamon mode and the X11 connection is 
unexpectedly lost.\n\
+Using an Emacs configured with --with-x-toolkit=lucid does not have this 
problem.");
+#endif
       f = fork ();
 #else /* NS_IMPL_COCOA */
       /* Under Cocoa we must do fork+exec as CoreFoundation lib fails in


[Improvements for the warning text are more than welcome]