gtk+3: disable Xinerama support

GTK+ has enabled by default support for Xinerama, but it's not a build
dependency so this can be enabled or disabled depending if xinerama has been
built previously.

This can cause problems with sstate, and result in situations where
PKG_CHECK_MODULES() for GTK+ can appear successful but the CFLAGS are not set.

(From OE-Core rev: c6862c8162bd79c45961a4b9f8f570a3d5346148)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-gnome/gtk+/gtk+3_3.4.4.bb

@@ -39,6 +39,7 @@ do_configure_prepend() {
 EXTRA_OECONF += " \
                  --disable-gtk2-dependency \
                  --disable-glibtest \
+                 --disable-xinerama \
                  --enable-modules \
                  --disable-cups \
 "