Inclusion of config.h in the example programs

[Tor Lillqvist <tml iki fi>]

Stephen Nestinger writes:
 > It appears that all of the gtk+-2.4.10 examples include config.h.

That is presumably quite unnecesary. It's also counter-productive, as
it might make people think that GTK's config.h file is supposed to be
available when compiling software that just uses GTK. Which is not the
case at all. If some developer package of GTK (or GLib, Pango, etc)
includes the config.h file, that's an error.

--tml