package/ratpoison: needs MMU

Fixes:
http://autobuild.buildroot.net/results/10c/10c0a41275ba53473c89881990ba608b7550b23a

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

package/ratpoison/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_RATPOISON
 	bool "ratpoison"
+	depends on BR2_USE_MMU
 	depends on BR2_PACKAGE_XORG7
 	select BR2_PACKAGE_FONTCONFIG
 	select BR2_PACKAGE_LIBERATION