libcdio: need mmu

Fixes:
http://autobuild.buildroot.net/results/92b/92b6513a10bed9018d64e1347c99ff6db96990eb/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libcdio/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LIBCDIO
 	bool "libcdio"
+	depends on BR2_USE_MMU # fork()
 	select BR2_PACKAGE_LIBICONV if !BR2_ENABLE_LOCALE
 	help
 	  The GNU Compact Disc Input and Control library.