fastd: needs mmu

Fixes:
http://autobuild.buildroot.net/results/87b/87bf97966cb802fc307ec9710725a3947ec33c39/

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

package/fastd/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_FASTD
 	bool "fastd"
+	depends on BR2_USE_MMU # fork()
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_LIBUECC
 	select BR2_PACKAGE_LIBSODIUM
@@ -21,4 +22,5 @@ config BR2_PACKAGE_FASTD_STATUS_SOCKET
 endif
 
 comment "fastd needs a toolchain w/ threads"
+	depends on BR2_USE_MMU
 	depends on !BR2_TOOLCHAIN_HAS_THREADS