Log Message:
Changes 3.0.20:
* Fix regression in 3.0.19 which causes incorrect fault handling if
  efax-gtk is given an invalid postscript file.
* Provide new Emitter/EmitterArg and SafeEmitter/SafeEmitterArg
  classes for thread-safe signalling.
* Provide a Callback::post() function which provides for thread-safe
  disconnection of a callback if the object whose method it
  encapsulates has been destroyed.

Changes 3.0.19:
* If the gtk+ version is >= 2.8.0 and X11 is the backend, use gdk
  X11 functions to move the program window to the current workspace
  if the user tries to start another instance.
* Include gtk/gtk.h, gdk/gdk.h and glib.h instead of individual
  gtk+/glib header files.
* Correct failure to print or view logfile if the logfile user
  setting does not have an absolute path name.
* Allow choice of priorities in Callback::post() function.  Provide
  Callback::Functor class wrapping Callback objects and further
  generalise Callback objects.
* Improve iconified tracking.
* Correct the order in which tests based on the definitions in
  config.h are carried out, when choosing header files to be included.
* Include fsync() call after flushing fdoutbuf stream buffer.
* Minor code layout improvements.