build world cross compile

[falcon17 at hushmail.com]

I would like to build 10-STABLE for arm on my amd64. I found some
instructions here
-https://wiki.freebsd.org/A_Brief_Guide_To_Cross_Compiling_FreeBSD(i
assume the third CPUTYPE example should be KERNCONF instead?)
all looks good, except that make.conf and src.conf examples do not say
a peep about arm! What are the right way of specifying these targets?
Do I need to build a special compiler before starting?
Thanks!