knock: needs mmu

Signed-off-by: Michael Rommel <rommel@layer-7.net>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/knock/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_KNOCK
 	bool "knock"
 	select BR2_PACKAGE_LIBPCAP
+	depends on BR2_USE_MMU # fork()
 	help
 	  A port knocking implementation.
 	  Provides a daemon and a user application. Port knocking can be