package/efl/libevas: explicitly disable X11 support

Fixes:
http://autobuild.buildroot.net/results/bfc/bfc52a6f12789055ad376b40a00bc94847760469/

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/efl/libevas/libevas.mk

@@ -65,6 +65,8 @@ endif
 ifeq ($(BR2_PACKAGE_LIBEVAS_X11),y)
 LIBEVAS_CONF_OPTS += --enable-software-xlib
 LIBEVAS_DEPENDENCIES += xlib_libX11 xlib_libXext
+else
+LIBEVAS_CONF_OPTS += --disable-software-xlib
 endif
 
 ifeq ($(BR2_PACKAGE_LIBEVAS_X11_GLX),y)