Added generic signal handling mechanism based on pipes to synchronize
signals with the main poll loop.

diff --git a/server/object.h b/server/object.h
index 256c99e..1815e24 100644
--- a/server/object.h
+++ b/server/object.h
@@ -145,6 +145,11 @@
 extern void close_registry(void);
 extern void registry_close_handle( struct object *obj, obj_handle_t hkey );
 
+/* signal functions */
+
+extern void init_signals(void);
+extern void close_signals(void);
+
 /* atom functions */
 
 extern void close_atom_table(void);