Firefox on a Pi2 fails in rust

[bob prohaska]

While playing with www/firefox on a Pi2 running
FreeBSD 11.3-STABLE #1 r351585 
make stops with
INFO: checking for rust target triplet... 
ERROR: Don't know how to translate armv6-unknown-freebsd11.3-gnueabihf for rustc

Far as I can tell lang/rust compiled without issue, is there a 
workaround? Ports are at revision 510853.

Thanks for reading,

bob prohaska