/etc/rc.d/network patch for Vagrant with Archlinux. Makes `gateway` not required.

gistfile1.diff

--- network.orig 
+++ network
@@ -25,16 +25,16 @@
 network_up() {
 	/usr/sbin/ip link set dev $interface up || return 1
 
 	if [[ $address ]]; then
-		for var in netmask gateway; do
+		for var in netmask ; do
 			if [[ -z ${!var} ]]; then
 				printf "${C_FAIL}Error: static address defined without $var!\n"
 				return 1
 			fi
 		done
 		/usr/sbin/ip addr add $address/$netmask dev $interface || return 1
-		/usr/sbin/ip route add default via $gateway || return 1
+		[[ $gateway ]] && { /usr/sbin/ip route add default via $gateway || return 1; }
 	else
 		/sbin/dhcpcd $DHCPCD_ARGS $interface || return 1
 	fi
 }