added "defined(MAPPED_ADDR_ENABLED)" for ip_2_ip6_hdr(), because it is also dependet on that option.
added "defined(MAPPED_ADDR_ENABLED)" for ip_2_ip6_hdr(), because it is also
dependet on that option.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame