parser: add typeof keyword for declarations

parser: add typeof keyword for declarations

Add a typeof keyword to automatically use the correct type in set and map
declarations.

table filter {
	set blacklist {
		typeof ip saddr
	}

	chain input {
		ip saddr @blacklist counter drop
	}
}

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>