gEDA-dev: DBUS binding to PCB actions

[DJ Delorie]

> OTOH, using the Raw C binding (as I started out trying to) does give the
> advantage of being able to work with Lesstif, etc.. IIRC, you need to
> add the file descriptor which DBUS uses for comms into the main GUI's
> poll / select loop to avoid having to poll manually and consume lots of
> CPU cycles.

This would be a far better option.  Xt has a hook for watching a file
descriptor (XtAppAddInput); Gtk should too.  We can add a hook to the
HID structure, something like:

  hidval watch_file (int fd, void *user_data, void (*callback)(int, void *));
  void unwatch_file (hidval which);

If using the raw C binding gets us Windows and generic Posix (solaris,
OS/X, etc), I'd rather use that.