package/x11r7/xserver_xorg-server: Explicitly disable glamor support when dependencies are not met

Fixes
http://autobuild.buildroot.net/results/b48/b48074089da770463f7ffcc27e385ac59456edc5/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/x11r7/xserver_xorg-server/xserver_xorg-server.mk

@@ -224,6 +224,8 @@ XSERVER_XORG_SERVER_CONF_OPTS += --enable-dri3
 ifeq ($(BR2_PACKAGE_HAS_LIBGL)$(BR2_PACKAGE_LIBEPOXY),yy)
 XSERVER_XORG_SERVER_DEPENDENCIES += libepoxy
 XSERVER_XORG_SERVER_CONF_OPTS += --enable-glamor
+else
+XSERVER_XORG_SERVER_CONF_OPTS += --disable-glamor
 endif
 else
 XSERVER_XORG_SERVER_CONF_OPTS += --disable-dri3 --disable-glamor