iputils: needs mmu

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/iputils/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_IPUTILS
 	bool "iputils"
 	select BR2_OPENSSL if BR2_INET_IPV6
+	depends on BR2_USE_MMU # fork()
 	help
 	  This package is set of small useful utilities for Linux networking.
 	  It includes complete versions of ping, traceroute, etc.