configuration problem detecting x headers

[Dennis Heuer <dh triple-media com>]

Having installed gtk+ from source, apps that link against gtk-x11 fail
because the gdk header files can't find X11 header files. Putting the
path to X11 into CFLAGS corrects the problem. It seems that the
configuration information to gtk+ is not fully complete and causes
problems on systems where things may not be found 'accidentially'
because they aren't in default places.

Regards,
Dennis Heuer