User visible:

Change fsys_set_options interface to allow returning data & err+data.
  fsys: fsys_t; options: data_t; do_children: int; err: error_t; result: data_t
Add error_t to hurd_types.defs.

Add notification calls to process.defs (and create process_notify.defs). 
(not yet)

Add file_exchange_contents (not yet)

Change file_getfh and fsys_getfile to use more convenient interface.

Remove hostid/hostname calls from process.defs.

Add serverport arg to auth_user_authenticate; change auth to use it to
abort auth_user_authenticate when it's dead.

Add io_revoke.


Not user visible:

Format of /var/login should be user:1 not user-1.
  [Or as subdirectories, if a server supplies directory ops anyway]