links: needs mmu

Fixes
http://autobuild.buildroot.net/results/1c1456b19d7483475430b390291240733dbbf21b

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/links/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LINKS
 	bool "links"
+	depends on BR2_USE_MMU # fork()
 	help
 	  Graphics and text mode WWW browser (kind of like lynx).