Removed DEFS "+=" mess that breaks recent automakes. INCLUDES is the

Removed DEFS "+=" mess that breaks recent automakes. INCLUDES is the

* gdk/Makefile.am, gtk/Makefile.am:

        Removed DEFS "+=" mess that breaks recent automakes.
        INCLUDES is the correct way to add to CFLAGS from Makefile.am.

* gdk/gdk.c, gdk/gdkglobals.c, gdk/gdkimage.c, gdk/gdkinput.c,
gdk/gdkpixmap.c, gdk/gdkthreads.c, gdk/gdkwindow.c,
gdk/gxid_lib.c, gtk/fnmatch.c, gtk/gtkclist.c, gtk/gtkmain.c,
gtk/testthreads.c:

        Include "config.h" instead of "../config.h".

        Now that DEFS works again, automake will automatically pass us
        the location of config.h in -I.